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Maltase
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Maltose
Ligand (NAG) interactions in Maltase-Glucoamylase
Interactions of oligosaccharides in Alpha-amylase

Maltase is an informal name for a family of enzymes that catalyze the hydrolysis of disaccharide maltose into two simple sugars of glucose. Maltases are found in plants, bacteria, yeast, humans, and other vertebrates.

Digestion of starch requires six intestinal enzymes. Two of these enzymes are luminal endo-glucosidases named alpha-amylases. The other four enzymes have been identified as different maltases, exo-glucosidases bound to the luminal surface of enterocytes. Two of these maltase activities were associated with sucrase-isomaltase (maltase Ib, maltase Ia). The other two maltases with no distinguishing characteristics were named maltase-glucoamylase (maltases II and III). The activities of these four maltases are also described as alpha-glucosidase because they all digest linear starch oligosaccharides to glucose.[1][2]

Structure

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Maltases are members of a group of intestinal enzymes called FamilyGH13 (Glycoside hydrolase family 13) that are responsible for breaking apart the α-glucosidase linkages of complex carbohydrates into simple to use glucose molecules.[3] The glucose molecules would then be used as a sort of "food" for cells to produce energy (Adenosine triphosphate) during Cellular respiration. The following are genes that can code for maltase:

  • Acid alpha-glucosidase which is coded on the GAA gene is essential to breakdown complex sugars called Glycogen into glucose.
  • Maltase-glucoamylase which is coded on the MGAM gene plays a role in the digestion of starches. It is due to this enzyme in humans that starches of plant origin are able to digested.[4]
  • Sucrase-isomaltase which is coded on the SI gene is essential for the digestion of carbohydrates including starch, sucrose and isomaltose.
  • Alpha-amylase 1 which is coded on the AMY1A gene is responsible of cleaving α-glucosidase linkages in oligosaccharides and polysaccharides in order to produce starches and glycogen for the previous enzymes to catalyze. Higher quantities of this gene in the brain have been shown to lower the risk of Alzheimer's disease.[5]

Mechanism

[edit]
Hydrolysis reaction of Maltose being broken at the 1-4 alpha-glucosidase linkage.

The mechanism of all FamilyGH13 enzymes is to break a α-glucosidase linkage by hydrolyzing it. Maltase focuses on breaking apart maltose, a disaccharide that is a link between 2 units of glucose, at the α-(1->4) bond. The rate of hydrolysis is controlled by the size of the substrate (carbohydrate size).[6]

Industrial applications

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Alpha-amylase has an important function in degradation of starches, so it is used frequently in the baking industry. It is mostly used a means of flavor enhancing to improve bread quality.[4] Without alpha-amylase, yeast would not be able to ferment.[7]

Maltose-glucoamylase is commonly used as a fermentation source as it is able to cut starch into maltose, which is then used for brewing beers and sake.[4]

Other than brewing, maltose glucoamylase has been studied by introducing specific inhibitors to stop the hydrolysis of the α-glucosidase linkages. By inhibiting the cleave of the linkages, scientists are hoping to devise a drug that is more efficient and less toxic to treating diabetes.[8]

History

[edit]

The history of maltase discovery began when Napoleon Bonaparte declared a continental blockade in his "Berlin decree" in 1806. This initiated the search for alternative sources of sugar. In 1833 French chemists Anselm Payen and Jean-Francois Persoz discovered a malt extract that converted starch into glucose which they called diastase at the time.[9] In 1880, H.T. Brown discovered mucosal maltase activity and differentiated it from diastase, now called amylase.[2] In the 1960s advances in protein chemistry allowed Arne Dahlqvist and Giorgio Semenza to fractionate and characterize small intestinal maltase activities. Both groups showed there were four major fractions of maltase activity that were intrinsic to two different peptide structures, sucrase-isomaltase and maltase-glucoamylase.[1][2][9][6] Fifty years later entering the genomic age, cloning and sequencing of the mucosal starch hydrolase confirmed Dahlqvist and Semenza's findings.[9]

Maltase deficiency

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Acid maltase deficiency (AMD) also known as Pompe disease was first described by Dutch pathologist JC Pompe in 1932.[10][11] AMD is a non sex linked autosomal recessive condition in which excessive accumulation of glycogen build up within lysosome vacuoles in nearly all types of cells all over the body.[10][11][12] It is one of the more serious glycogen storage diseases affecting muscle tissue.[13]

AMD is categorized into three separate types based on the age of onset of symptoms in the affected individual. Infantile (Type a), childhood (Type b), and adulthood (Type c). The type of AMD is determined by the type of gene mutation localized on 17q23. Mutation type will determine production level of acid maltase. AMD is extremely fatal. Type a generally die of heart failure prior to age one. Type b die of respiratory failure between ages three to twenty-four. Type c die of respiratory failure 10–20 years of the onset of symptoms.[13]

Comparative physiology

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Vampire bats are the only vertebrates known to not exhibit intestinal maltase activity.[14]

See also

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References

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[edit]
Revisions and contributorsEdit on WikipediaRead on Wikipedia

Maltase

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Maltase, also known as α-glucosidase, is a that catalyzes the of the into two molecules of glucose, facilitating the final stage of breakdown in the . In humans, maltase activity is primarily provided by the N-terminal domain of the maltase-glucoamylase (MGAM) complex, a membrane-bound anchored to the of enterocytes. This enzyme complex works in tandem with pancreatic and other mucosal to convert dietary starches and oligosaccharides into absorbable monosaccharides, essential for energy metabolism. The MGAM enzyme consists of two catalytic subunits: the N-terminal maltase domain (ntMGAM), which preferentially hydrolyzes linear α-1,4-linked glucosides like and , and the C-terminal glucoamylase domain (ctMGAM), which exhibits broader exo-glucosidase activity on similar substrates. Structurally, ntMGAM features a shallow pocket with subsites that accommodate α-1,4-linked glucose units, enabling high specificity (kcat/Km ≈ 26 s⁻¹ mM⁻¹ for ) while showing low affinity for branched α-1,6-linkages like those in . This specificity complements the sucrase-isomaltase (SI) complex, which handles branched structures, ensuring efficient terminal digestion of complex carbohydrates. Maltase plays a critical role in postprandial glucose by releasing glucose for absorption, influencing insulin secretion and . Deficiencies in MGAM can lead to maltase deficiency, a form of malabsorption characterized by osmotic and after ingestion, though it is rarer than deficiency. Beyond humans, maltase homologs are found in , , and , where they support mobilization during or processes. Due to its involvement in glucose production, MGAM is a therapeutic target for α-glucosidase inhibitors like , used to manage by slowing digestion.

Overview and Biological Significance

Definition and Primary Function

Maltase, also known as alpha-glucosidase, is a classified under EC 3.2.1.20 that catalyzes the of terminal non-reducing 1,4-linked alpha-D-glucose residues from oligosaccharides, with particular specificity for the . This belongs to a group of alpha-glucosidases that primarily target exohydrolysis of alpha-1,4-glucosidic linkages, enabling the breakdown of into simpler sugar units. The primary biochemical reaction facilitated by maltase is the hydrolysis of maltose, a disaccharide composed of two glucose molecules linked by an alpha-1,4-glycosidic bond, into two molecules of D-glucose. This process can be represented by the equation: Maltose+H2O→2D-Glucose\text{Maltose} + \text{H}_2\text{O} \rightarrow 2 \text{D-Glucose} This reaction occurs under physiological conditions and is essential for converting dietary disaccharides into absorbable monosaccharides. In , maltase plays a in the final stages of digestion within the , where it acts on produced by the action of salivary and pancreatic alpha-amylase on complex carbohydrates. By liberating free glucose, maltase enables its rapid absorption across the into the bloodstream, supporting energy production through and subsequent metabolic pathways. This function is primarily associated with the neutral form of maltase, which operates at the neutral pH of the intestinal lumen and is the dominant isoform in digestive processes. In contrast, the acid maltase variant functions in the acidic environment of lysosomes, where it degrades , but the neutral isoform remains the key player in extracellular breakdown.

Natural Occurrence and Distribution

Maltase, also known as α-glucosidase (EC 3.2.1.20), is a ubiquitous present across eukaryotes, including , fungi, and animals, as well as prokaryotes such as . In animals, maltase is primarily located in the of epithelial cells in humans, where it functions as part of the sucrase-isomaltase complex and maltase-glucoamylase. This positioning facilitates the of derived from dietary digestion. In plants, maltase occurs as an endocellular enzyme in all species, residing in germinated and ungerminated seeds, leaves, and roots. It is particularly prominent in seeds and germinating tissues, where it contributes to starch mobilization during early growth stages. Microbial production of maltase is notable in eukaryotes like brewing yeasts, such as Saccharomyces cerevisiae, and prokaryotes including bacteria like Halomonas species, supporting processes in industrial fermentation. In S. cerevisiae, maltase genes are clustered in telomeric regions and enable efficient utilization of maltose in beer production. Expression of maltase is regulated by in various organisms, often induced by substrates like , and features tissue-specific isoforms; for instance, in humans, distinct isoforms such as maltase-glucoamylase and sucrase-isomaltase predominate in the and respond to dietary levels. In , maltase synthesis is modulated by availability, with regulators controlling activation during .

Molecular Properties

Protein Structure

Maltase-glucoamylase (MGAM), the primary intestinal form of maltase, belongs to family 31 (GH31), a of retaining enzymes that catalyze the of α-glycosidic linkages through a double-displacement mechanism. This classification places MGAM alongside other α-glucosidases, distinguishing it from related starch-degrading enzymes in GH13, with its catalytic machinery adapted for exo-acting specificity on and related oligosaccharides. The protein features a modular, multi-domain structure optimized for membrane association and substrate interaction. The N-terminal catalytic subunit, responsible for maltase activity, adopts a canonical (β/α)8 barrel fold—commonly referred to as the —comprising eight parallel β-strands surrounded by α-helices, which forms the core of the . This domain is flanked by accessory subdomains, including an N-terminal β-sandwich and C-terminal extensions that contribute to substrate binding and specificity. The C-terminal glucoamylase subunit shares structural homology but exhibits distinct binding pockets, enabling sequential processing of α-1,4-linked glucans. Overall, the architecture ensures efficient docking of linear oligosaccharides at the enzyme's surface. Central to catalysis are conserved residues within the TIM barrel's active site pocket. In the human N-terminal domain, aspartic acid at position 443 (Asp443) acts as the nucleophilic residue, forming a covalent glycosyl-enzyme intermediate, while aspartic acid at position 542 (Asp542) serves as the acid/base catalyst, protonating the leaving group and facilitating hydrolysis. These residues, embedded in a WIDMNE motif typical of GH31, are essential for the retaining stereochemistry observed in product formation. The mature human intestinal MGAM has a molecular weight of approximately 100-120 for each catalytic domain, though the full-length, glycosylated protein migrates at 285-335 on due to extensive post-translational modifications. These include at multiple sites (e.g., Asn822) and on a serine/threonine-rich stalk region, which stabilize the protein, protect it from , and mediate its anchoring to the brush-border via a type II signal-anchor sequence near the . Such modifications are critical for the enzyme's localization and function in the .

Catalytic Mechanism

Maltase, as the N-terminal catalytic domain of human maltase-glucoamylase (ntMGAM), functions as a retaining α-glucosidase, hydrolyzing α-1,4-glycosidic bonds through a double-displacement mechanism that preserves the anomeric configuration of the released glucose. This process involves two main stages: glycosylation, where a covalent glucosyl-enzyme intermediate forms, and deglycosylation, where water hydrolyzes this intermediate to release the product. The active site, located within a (β/α)8 barrel fold, accommodates the substrate's non-reducing end at the -1 subsite and reducing end at the +1 subsite. In the first step, substrate binding positions the α-1,4-linked glucosyl unit in the , with the glycosidic oxygen aligned for cleavage. The catalytic , Asp443, performs a nucleophilic attack on the anomeric carbon of the -1 glucosyl residue, facilitated by of the glycosidic oxygen by the acid/base catalyst Asp542, leading to departure of the and formation of a covalent β-glucosyl-Asp443 intermediate via an oxocarbenium ion-like . Stabilizing residues such as Arg526 and Asp327 further assist by interacting with the substrate and . During deglycosylation, Asp542 deprotonates a molecule, which then attacks the anomeric carbon of the glucosyl-enzyme intermediate, hydrolyzing the and regenerating the free while releasing the second glucose molecule. This glycosylation step is typically rate-limiting, with an activation free energy barrier of approximately 15.8 kcal/mol. Kinetic studies indicate that ntMGAM exhibits a Michaelis constant (Km) for of about 4.3 mM, reflecting moderate substrate affinity suitable for intestinal digestion. The operates optimally at a neutral of 6.0–7.0, aligning with the physiological conditions of the . Maltase displays specificity for and short-chain maltodextrins (up to four glucose units), efficiently cleaving terminal α-1,4 linkages but showing negligible activity on longer polymeric chains, which distinguishes it from endo-acting amylases. Inhibitors such as competitively bind the with a Ki of 62 μM, mimicking the substrate's oxocarbenium and blocking .

Applications and Uses

Industrial Applications

Commercial production of maltase, also known as α-glucosidase, primarily involves microbial fermentation using strains such as Aspergillus niger and Bacillus licheniformis. In one established method, the enzyme is produced through submerged fermentation of genetically engineered Trichoderma reesei expressing the α-glucosidase gene from A. niger, followed by broth recovery, purification via ultrafiltration, and formulation with stabilizers like dextrose and sodium benzoate to achieve an activity of 1650–2140 units per gram. Similarly, B. licheniformis strains, such as KIBGE-IB4, yield high levels of extracellular maltase under optimized conditions of 37°C, pH 7.0, and wheat starch as a carbon source, enabling scalable bioprocessing for industrial supply. In the , maltase plays a key role in processing by hydrolyzing to glucose, which enhances efficiency and product sweetness. It is commonly applied in to break down from malted flours, increasing available glucose for and improving rise and volume. In , the hydrolyzes residual in , boosting glucose availability for and thereby increasing alcohol yield while reducing unfermentable sugars in the final . Additionally, maltase serves as an adjunct in the production of glucose syrups, including those used for , where it facilitates the conversion of intermediates from liquefaction to fermentable glucose. Maltase supplementation in improves in animals like pigs by enhancing the breakdown of from dietary carbohydrates, leading to better utilization and growth performance. It is incorporated into multi-enzyme blends to address limitations in endogenous activity during , reducing digestive inefficiencies in high-starch diets. The global market for , including maltase, is experiencing growth driven by rising demand in and animal , with the sector reaching approximately USD 8 billion in 2025, reflecting increased adoption in gluten-free and efficient feed formulations amid pressures. This expansion underscores maltase's economic importance in optimizing bioconversions for low-carb and specialty products.

Therapeutic and Research Uses

In therapeutic contexts, recombinant acid α-glucosidase (a lysosomal isoform also known as acid maltase), marketed as alglucosidase alfa, serves as the cornerstone of enzyme replacement therapy (ERT) for Pompe disease, a lysosomal storage disorder caused by acid alpha-glucosidase deficiency. Approved by the FDA in 2006, this recombinant human enzyme is administered intravenously to replenish the deficient lysosomal enzyme, thereby reducing glycogen accumulation in muscles and improving cardiac and respiratory function in patients. Clinical studies have demonstrated that early initiation of alglucosidase alfa at higher doses, such as 40 mg/kg weekly, significantly enhances survival rates and motor abilities in infantile-onset Pompe disease compared to lower doses. Diagnostic applications of maltase leverage enzymatic assays to measure activity levels in small intestinal biopsies, aiding the identification of malabsorption syndromes such as disaccharidase deficiencies. These assays, performed on duodenal tissue obtained via endoscopy, quantify maltase (alpha-glucosidase) activity in units per gram of protein, with values below 100 U/g protein indicating deficiency and correlating with symptoms like osmotic diarrhea from undigested maltose. Such biopsy-based testing remains the gold standard for confirming maltase-related malabsorption, as it directly assesses mucosal enzyme function and distinguishes primary genetic defects from secondary causes like celiac disease. Research efforts in have focused on enhancing the thermostability of alpha-glucosidases, including maltases, through and to suit harsh industrial conditions. For instance, proline substitutions at flexible residues in alpha-glucosidase from increased its at 60°C by over twofold, preserving catalytic efficiency for . Similarly, of a Thermus thermophilus alpha-glucosidase yielded variants with improved thermal stability and transglycosylation activity, enabling applications in synthesis. Studies on the glycoside hydrolase family 13 (GH13), which encompasses many maltases and alpha-glucosidases, explore their role in biofuel production by facilitating complete starch hydrolysis to fermentable glucose. A GH13 alpha-glucosidase from alkaliphilic Bacillus pseudofirmus efficiently degrades maltooligosaccharides from liquefied starch, complementing amylases in bioethanol processes and reducing fermentation inhibitors. These enzymes' ability to hydrolyze short-chain starch derivatives under alkaline conditions supports sustainable biofuel conversion from starch-rich biomass like corn. Emerging approaches target acid α-glucosidase deficiencies in Pompe disease, with ongoing trials as of 2025 evaluating (AAV) vectors to deliver functional GAA genes. Phase I studies of liver-directed AAV have shown sustained expression and clearance in late-onset Pompe patients, offering potential for long-term correction without repeated infusions. Autologous is also under investigation, aiming to provide lifelong GAA production via transduction. In diabetes research, , are utilized to modulate postprandial glucose control by delaying in the intestine. Voglibose competitively inhibits maltase activity, reducing glucose absorption and lowering HbA1c levels by 0.5–1% in patients when added to standard therapies. Long-term studies confirm its efficacy in suppressing without significant impact on insulin secretion.

Historical Development

Discovery and Early Characterization

The discovery of maltase, the responsible for hydrolyzing into glucose, emerged from early investigations into digestion and processes in the . In 1833, French chemist Anselme Payen isolated from extracts, marking the first identification of an capable of breaking down into ; this laid the groundwork for recognizing subsequent steps in , though itself is now known as α-amylase. Payen's work demonstrated the catalytic activity in and extracts, highlighting the presence of factors that further process , which would later be attributed to maltase. In 1880, British chemist H.T. Brown discovered maltase activity in intestinal mucosa and differentiated it from (), establishing its role in animal digestive tissues. By the late , the specific activity of maltase was delineated through studies on . In 1894, German chemist identified maltase in beer extracts, showing its selective of via α-1,4-glycosidic bonds while distinguishing it from other glucosidases like . 's experiments emphasized the enzyme's role in low organisms, such as , where it facilitated the conversion of to fermentable glucose. This characterization was pivotal, as it introduced the concept of enzyme specificity, famously analogized by to a mechanism. In the early , Eduard Buchner's pioneering work on cell-free further linked maltase to metabolic processes. In 1897, Buchner demonstrated that extracts without intact cells could ferment sugars, including , producing alcohol and ; this implied the coordinated action of enzymes like maltase in breaking down to glucose prior to further metabolism. Buchner's findings in the and subsequent refinements in the 1920s underscored maltase's integral role in fermentation, influencing early biochemical assays that detected its activity through glucose liberation. Early biochemical assays for maltase relied on measuring glucose production from hydrolysis in tissue extracts. By the 1920s and 1930s, researchers used tests, such as the Bertrand or Shaffer-Somogyi methods, to quantify activity in pancreatic and intestinal extracts, where maltase was detected alongside . These assays confirmed maltase's presence in animal tissues, distinguishing its neutral pH optimum from acidic variants and establishing its function in digestive extracts. During the , maltase was increasingly recognized as a key component of intestinal disaccharidases, with efforts to separate its activity from sucrase (). Swedish A. Dahlqvist's studies on and mucosa revealed that maltase activity often co-occurred with sucrase but could be partially distinguished through and activity ratios, such as maltase-to-invertase quotients around 0.6 in jejunal samples. This separation highlighted maltase's independent contributions to , paving the way for understanding disaccharidase complexes. Key milestones in the 1960s included the identification of multiple maltase isoforms, notably neutral and acid variants. The neutral isoform, active at physiological pH in intestinal mucosa, was characterized through fractionation studies showing its brush-border localization. Concurrently, the acid isoform (acid α-glucosidase) was identified by Henri-Géry Hers in 1963 as a lysosomal enzyme deficient in Pompe disease (glycogen storage disease type II), with assays confirming its role in glycogen breakdown at low pH. These distinctions clarified maltase's diverse physiological roles across cellular compartments.

Advances in Understanding

In the late , significant progress was made in the molecular of lysosomal maltase (GAA), with the isolation of a cDNA clone for the , enabling initial insights into its genetic basis and expression patterns. This work laid the foundation for understanding GAA deficiencies in Pompe disease. Concurrently, early mapping efforts positioned the intestinal maltase-glucoamylase (MGAM) gene on , though full occurred later. By the , the cDNA for MGAM was cloned and sequenced, revealing its homology to sucrase-isomaltase and confirming its role in . Advancements in during the 1990s included the determination of crystal structures for GH13 family members, such as the 1984 structure of TAKA-amylase, which elucidated the conserved (β/α)8-barrel fold and (Asp-Glu-Asp) in the , providing a template for understanding maltase mechanisms across the family. These structures highlighted substrate binding pockets and informed subsequent modeling of maltase variants. In the 2000s, full genomic sequencing of MGAM confirmed its location at 7q34 and its evolutionary duplication from sucrase-isomaltase, spanning approximately 82 kb with complementary starch-hydrolyzing functions. Genetic sequencing in the 2000s linked MGAM variants to deficiencies, with reports of congenital maltase-glucoamylase deficiency associated with sucrase and impairments, often involving multiple defects due to shared regulatory pathways. Emerging evidence also pointed to maltase's role in interactions, as impaired in MGAM-deficient models led to altered gut bacterial composition, with reduced Bacteroidetes and increased Firmicutes/Bacteroidetes ratios promoting . The 2010s brought high-resolution crystal structures of human MGAM subunits, including the N-terminal domain at 2.0 Å resolution in apo form and with , revealing distinct substrate specificities between N- and C-terminal catalytic sites and inhibitor binding modes. CRISPR/Cas9 applications advanced functional studies, such as generating GAA knockout mice in 2022 to model Pompe disease phenotypes, including glycogen accumulation and muscle , which validated regulatory elements for expression. For Pompe , next-generation enzyme replacement therapies (ERTs) progressed, with avalglucosidase alfa approved in 2021 and cipaglucosidase alfa/ in 2023 following phase 3 trials demonstrating improved glycogen clearance and respiratory function over first-generation alglucosidase alfa. Current research highlights gaps in understanding microbial maltase diversity and its regulation across species, while emerging studies emphasize maltase's modulation of through availability, influencing host and .

Clinical and Physiological Aspects

Maltase Deficiency Disorders

Isolated congenital maltase-glucoamylase (MGAM) deficiency is a rare autosomal recessive disorder caused by mutations in the MGAM gene, leading to deficient neutral maltase activity in the intestinal and impaired of and other α-1,4-linked glucosides. Symptoms include chronic diarrhea, , and of starches, typically presenting in infancy or , though is unknown with only case reports documented. Diagnosis involves disaccharidase assays from intestinal biopsies showing low MGAM activity, with management limited to low-starch diets; no specific enzyme replacement is available. Multiple enzyme deficiencies, including MGAM alongside sucrase or , have been reported in some cases. Maltase deficiency disorders primarily encompass two distinct conditions: congenital sucrase-isomaltase deficiency (CSID), which impairs the neutral maltase activity of the sucrase-isomaltase enzyme complex in the intestinal (contributing approximately 80% of total maltase activity), and Pompe disease (, or GSD II), resulting from lysosomal acid alpha-glucosidase (GAA) deficiency. CSID is an autosomal recessive disorder caused by mutations in the SI gene, leading to reduced or absent sucrase-isomaltase function and consequent maldigestion of , starches, and , with secondary reduction in maltase activity. Symptoms typically manifest in infancy or and include chronic osmotic , abdominal , gas, and following ingestion of or starch-containing foods, often resulting in if untreated. The prevalence of the classical form of CSID is estimated at approximately 1 in 5,000 individuals in European populations, though it is higher among indigenous groups in and . is confirmed through a , which detects elevated hydrogen levels indicative of , or via disaccharidase from small bowel , with for SI variants providing supportive evidence. Management focuses on dietary modification, including a low-starch and -free diet to alleviate symptoms, supplemented by sacrosidase replacement in many cases. Pompe disease, also autosomal recessive, arises from mutations in the GAA gene, causing deficient lysosomal acid activity and progressive accumulation in lysosomes, particularly affecting skeletal, cardiac, and respiratory muscles. Clinical manifestations vary by onset: infantile-onset Pompe presents with severe , , and within the first year of life, while late-onset forms feature progressive , respiratory insufficiency, and fatigue emerging in childhood or adulthood. Worldwide prevalence is approximately 1 in 40,000 individuals. involves enzyme activity assays on dried blood spots, leukocytes, or fibroblasts to measure GAA levels, often combined with to identify GAA variants. Treatment relies on enzyme replacement (ERT) with recombinant GAA (e.g., alglucosidase alfa), which has been the standard since 2006; as of 2025, updates include higher dosing regimens (up to 40 mg/kg weekly) and more frequent infusions to improve outcomes in infantile-onset cases, alongside supportive therapies for respiratory and cardiac complications.

Comparative Roles Across Species

In mammals, including humans, maltase primarily functions as a membrane-bound in the , where maltase-glucoamylase (MGAM) hydrolyzes and other α-1,4-linked gluco-oligosaccharides derived from dietary into glucose, facilitating postprandial glucose absorption and . A distinct lysosomal form, acid α-glucosidase (GAA), operates within lysosomes to degrade and other glucans, playing a key role in by processing autophagocytosed material for cellular recycling. In , maltase, often referred to as α-glucosidase, exists as a soluble in the of cells, particularly within amyloplasts, where it converts —produced by β-amylase during mobilization—into glucose to support energy demands during seed germination. For instance, in (Hordeum vulgare), this cytosolic maltase is essential for efficient breakdown in the , enabling glucose supply to the growing without direct involvement in initial granule . Microbial maltases, classified as α-glucosidases, vary in localization and function across and fungi, often operating as secreted or intracellular enzymes to support rapid utilization during processes. In fungi such as yeasts, intracellular maltase facilitates uptake and for production, while in like , secreted forms contribute to extracellular degradation. Thermophilic microbes exhibit adaptations with higher in their maltases; for example, in thermotolerant yeasts like Ogataea polymorpha, these enzymes retain activity at elevated temperatures, enhancing efficiency in high-heat environments. Recent studies (post-2020) highlight microbial α-glucosidases' roles in gut communities, where they metabolize host-derived , influencing carbohydrate flux and interspecies interactions in diverse ecosystems. Evolutionarily, maltases belong to the family 13 (GH13), which shows strong conservation across eukaryotes and prokaryotes, reflecting ancient origins in α-glucan metabolism. Adaptations within GH13 include expanded substrate ranges in , such as lepidopterans, where maltase subfamilies have diverged to hydrolyze alongside , enabling dietary flexibility on and plant saps. Physiologically, maltase activity varies with dietary niches; in herbivores like certain and birds, intestinal maltase levels are elevated compared to carnivores, optimizing the hydrolysis of from plant starches, though not directly from cellulose breakdown products. This enhancement supports efficient energy extraction from fibrous, starch-rich vegetation, contrasting with lower activities in omnivores or strict carnivores.

References

  1. https://pmc.ncbi.nlm.nih.gov/articles/PMC2878540/
  2. https://pmc.ncbi.nlm.nih.gov/articles/PMC2666363/
  3. https://pubmed.ncbi.nlm.nih.gov/29762372/
  4. https://pmc.ncbi.nlm.nih.gov/articles/PMC7329151/
  5. https://pmc.ncbi.nlm.nih.gov/articles/PMC4807107/
  6. https://pmc.ncbi.nlm.nih.gov/articles/PMC8539097/
  7. https://enzyme.expasy.org/EC/3.2.1.20
  8. https://iubmb.qmul.ac.uk/enzyme/EC3/2/1/20.html
  9. https://www.genome.jp/dbget-bin/www_bget?ec:3.2.1.20
  10. https://www.sciencedirect.com/science/article/pii/0014488684902048
  11. https://www.sciencedirect.com/topics/neuroscience/alpha-glucosidase
  12. https://journals.asm.org/doi/10.1128/AEM.07514-11
  13. https://pubmed.ncbi.nlm.nih.gov/29762369/
  14. https://www.frontiersin.org/journals/molecular-biosciences/articles/10.3389/fmolb.2023.1160860/full
  15. https://www.pnas.org/doi/10.1073/pnas.0237170100
  16. https://www.sciencedirect.com/science/article/pii/S2214514117300909
  17. https://pmc.ncbi.nlm.nih.gov/articles/PMC1636176/
  18. https://cornerstone.lib.mnsu.edu/cgi/viewcontent.cgi?article=2136&context=etds
  19. https://pubmed.ncbi.nlm.nih.gov/29762370/
  20. https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0198744
  21. https://www.cazypedia.org/index.php/Glycoside_Hydrolase_Family_31
  22. https://www.uniprot.org/uniprotkb/O43451/entry
  23. https://datasheets.scbt.com/sc-70086.pdf
  24. https://pubs.acs.org/doi/10.1021/acs.jpcb.8b01321
  25. https://www.fda.gov/files/food/published/GRAS-Notice-000703--Alpha-glucosidase-from-Aspergillus-niger-produced-by-Trichoderma-reesei.pdf
  26. https://www.researchgate.net/publication/265255998_Enhanced_production_of_maltase_a-glucosidase_from_newly_isolated_strain_of_Bacillus_licheniformis_KIBGE-IB4
  27. https://asbe.org/article/maltase/
  28. https://coloradobeer.org/tech-safety-posts/enzymes-in-brewing/
  29. https://pmc.ncbi.nlm.nih.gov/articles/PMC9047707/
  30. https://en.engormix.com/pig-industry/enzymes-swine-nutrition/contributions-enzyme-technology-poultry_a49554/
  31. https://www.grandviewresearch.com/industry-analysis/industrial-enzymes-market
  32. https://pmc.ncbi.nlm.nih.gov/articles/PMC6881636/
  33. https://pmc.ncbi.nlm.nih.gov/articles/PMC12419020/
  34. https://pmc.ncbi.nlm.nih.gov/articles/PMC3129995/
  35. https://pubmed.ncbi.nlm.nih.gov/34822769/
  36. https://pmc.ncbi.nlm.nih.gov/articles/PMC10226910/
  37. https://ltd.aruplab.com/Tests/Pub/3002037
  38. https://journals.lww.com/eurojgh/fulltext/2006/01000/diagnostic_value_of_measuring_disaccharidase.181.aspx
  39. https://link.springer.com/article/10.1007/s12257-022-0129-2
  40. https://bmcbiotechnol.biomedcentral.com/articles/10.1186/s12896-015-0197-x
  41. https://www.sciencedirect.com/science/article/abs/pii/S0141813017303380
  42. https://www.cazypedia.org/index.php/Glycoside_Hydrolase_Family_13
  43. https://www.sciencedirect.com/science/article/pii/S1525001623000771
  44. https://pmc.ncbi.nlm.nih.gov/articles/PMC12340210/
  45. https://pmc.ncbi.nlm.nih.gov/articles/PMC3919386/
  46. https://pmc.ncbi.nlm.nih.gov/articles/PMC4723535/
  47. https://onlinelibrary.wiley.com/doi/10.1097/MPG.0000000000001960
  48. https://www.britannica.com/biography/Anselme-Payen
  49. https://onlinelibrary.wiley.com/doi/10.1097/MPG.0000000000001955
  50. https://www.encyclopedia.com/people/science-and-technology/chemistry-biographies/emil-herman-fischer
  51. https://royalsocietypublishing.org/doi/pdf/10.1098/rspb.1907.0027
  52. https://www.nobelprize.org/uploads/2018/06/buchner-lecture.pdf
  53. https://mechanism.ucsd.edu/~bill/teaching/w22/phil147/buchner.1897.pdf
  54. https://pubmed.ncbi.nlm.nih.gov/13719332/
  55. https://actachemscand.ki.ku.dk/pdf/acta_vol_13_p0945-0953.pdf
  56. https://pubmed.ncbi.nlm.nih.gov/4744396/
  57. https://cdnsciencepub.com/doi/10.1139/o82-129
  58. https://www.medlink.com/articles/pompe-disease
  59. https://pubmed.ncbi.nlm.nih.gov/6426997/
  60. https://pmc.ncbi.nlm.nih.gov/articles/PMC387196/
  61. https://pmc.ncbi.nlm.nih.gov/articles/PMC8063059/
  62. https://pmc.ncbi.nlm.nih.gov/articles/PMC298790/
  63. https://onlinelibrary.wiley.com/doi/10.1002/j.1536-4801.2002.tb07889.x
  64. https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0024585
  65. https://www.rcsb.org/structure/2QLY
  66. https://www.accessdata.fda.gov/scripts/opdlisting/oopd/detailedIndex.cfm?cfgridkey=411913
  67. https://www.accessdata.fda.gov/scripts/opdlisting/oopd/detailedIndex.cfm?cfgridkey=601617
  68. https://pubmed.ncbi.nlm.nih.gov/12394387/
  69. https://www.orpha.net/en/disease/detail/35122
  70. https://pmc.ncbi.nlm.nih.gov/articles/PMC11114242/
  71. https://www.ncbi.nlm.nih.gov/books/NBK470558/
  72. https://www.accessdata.fda.gov/drugsatfda_docs/nda/98/20772stat_rev.pdf
  73. https://pmc.ncbi.nlm.nih.gov/articles/PMC8298246/
  74. https://rarediseases.org/rare-diseases/pompe-disease/
  75. https://medlineplus.gov/genetics/condition/pompe-disease/
  76. https://pmc.ncbi.nlm.nih.gov/articles/PMC3298105/
  77. https://www.tandfonline.com/doi/full/10.1080/14656566.2025.2491508
  78. https://www.nature.com/articles/gim200650
  79. https://pmc.ncbi.nlm.nih.gov/articles/PMC2949326/
  80. https://www.mdpi.com/2218-273X/14/5/573
  81. https://pmc.ncbi.nlm.nih.gov/articles/PMC3032477/
  82. https://annalsmicrobiology.biomedcentral.com/articles/10.1007/s13213-011-0340-4
  83. https://pmc.ncbi.nlm.nih.gov/articles/PMC5074314/
  84. https://pubmed.ncbi.nlm.nih.gov/40425014/
  85. https://www.nature.com/articles/srep45787
  86. https://www.sciencedirect.com/science/article/pii/S0021925817493732
  87. https://www.journals.uchicago.edu/doi/10.1086/422228
  88. https://experts.boisestate.edu/en/publications/low-activities-of-digestive-enzymes-in-the-guts-of-herbivorous-gr
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