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Diastase
Diastase
Diastase
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A diastase (/ˈdaɪəsteɪz/; from Greek διάστασις, "separation") is any one of a group of enzymes that catalyses the breakdown of starch into maltose. For example, the diastase α-amylase degrades starch to a mixture of the disaccharide maltose; the trisaccharide maltotriose, which contains three α (1-4)-linked glucose residues; and oligosaccharides, known as dextrins, that contain the α (1-6)-linked glucose branches.[1]

Diastase was the first enzyme discovered.[2] It was extracted from malt solution in 1833 by Anselme Payen and Jean-François Persoz, chemists at a French sugar factory.[3] The name "diastase" comes from the Greek word διάστασις (diastasis) (a parting, a separation), because when beer mash is heated, the enzyme causes the starch in the barley seed to transform quickly into soluble sugars and hence the husk to separate from the rest of the seed.[4][5] Today, "diastase" refers to any α-, β-, or γ-amylase (all of which are hydrolases) that can break down carbohydrates.[6]

The commonly used -ase suffix for naming enzymes was derived from the name diastase.[7]

When used as a pharmaceutical drug, diastase has the ATC code A09AA01 (WHO).

Amylases can also be extracted from other sources including plants, saliva and milk.

Clinical significance

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Urine diastase is useful in diagnosing uncertain abdominal cases (especially when pancreatitis is suspected), stones in the common bile duct (choledocholithiasis), jaundice and in ruling out post-operative injury to the pancreas; provided that the diastase level is correlated with clinical features of the patient.[8]

Diastase is also used in conjunction with periodic acid–Schiff stain in histology. For example, glycogen is darkly stained by PAS but can be dissolved by diastase. Fungi, on the other hand, stain darkly with PAS even after treatment by diastase.

See also

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References

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Diastase

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from Grokipedia
Diastase is a complex of amylolytic enzymes, primarily α- and β-amylases, that catalyze the of internal α-1,4-glycosidic bonds in and , converting them into , glucose, and dextrins. First isolated in 1833 from malt extract by French chemists Anselme Payen and Jean-François Persoz, it marked the inaugural discovery of an enzyme, laying foundational groundwork for enzymology. The term "diastase," derived from the Greek diastasis meaning "separation," reflects its role in breaking down complex carbohydrates during processes like in cereals. Historically, Payen and Persoz precipitated diastase from barley malt infusion using alcohol, observing its ability to saccharify at moderate temperatures while noting its inactivation by heat above 60°C, a property that distinguished it from inorganic catalysts. This nature—optimal activity around 50–60°C and denaturation beyond—remains a key characteristic, influencing its measurement in contexts like quality via the diastase number (expressed in Schade units or Göthe units), where levels below 8 indicate overheating or aging. In 1894, Japanese Jokichi Takamine advanced the field by patenting the first commercial microbial diastase, Taka-diastase, derived from fermentation, enabling scalable production beyond plant sources. Diastase's applications span industry, medicine, and research, underscoring its versatility. In and , it facilitates conversion to fermentable sugars during , with diastatic power (DP) quantifying enzymatic activity in —typically 120–160°Lintner for base malts—to optimize fermentability and flavor. Fungal diastase serves as a digestive in pharmaceuticals, enhancing breakdown for conditions like , pancreatic insufficiency, and , often combined with in syrups to alleviate and improve nutrient uptake. In , it digests in periodic acid-Schiff (PAS) staining protocols to distinguish it from other mucosubstances, aiding pathological diagnoses. Additionally, in and , it improves dough handling and sugar release, while its role in production highlights ongoing biotechnological relevance.

Definition and Overview

Etymology and Terminology

The term "diastase" derives from the Greek roots dia- (διά, meaning "through" or "apart") and stasis (στάσις, meaning "standing" or "separation"), evoking the concept of "separation" or "setting apart" in reference to its role in breaking down starch. It was coined in 1833 by French chemists Anselme Payen and Jean-François Persoz upon isolating a starch-hydrolyzing substance from malt extract. Historically, "diastase" served as a broad descriptor for any enzymatic capable of hydrolyzing into simpler sugars, encompassing what are now recognized as multiple related enzymes. This generic usage persisted in early enzymology but has since been supplanted by more specific nomenclature. In contemporary biochemistry, "diastase" is considered an outdated label, with precise terms like α-amylase (EC 3.2.1.1) and β-amylase (EC 3.2.1.2) used to denote distinct starch-degrading enzymes based on their catalytic specificities.

General Function

Diastase enzymes catalyze the of , a complex composed of and , into simpler sugars such as and glucose, facilitating the release of stored in reserves across various organisms. This enzymatic action is essential for energy mobilization, as it converts insoluble, high-molecular-weight into soluble, metabolizable monosaccharides and disaccharides that can be absorbed and utilized in . The catalytic processes of diastase involve both endohydrolysis by α-amylase, which randomly cleaves internal α-1,4-glycosidic bonds in the chains and the linear segments of , yielding oligosaccharides like and dextrins as intermediate products, and exohydrolysis by , which successively removes units from the non-reducing ends of these chains. Together, these endo- and exo-acting mechanisms enable efficient degradation of the structure into primarily and limit dextrins. In and , diastase initiates breakdown in the oral cavity through salivary forms, producing initial oligosaccharides that continue to be processed in the for nutrient absorption. During seed germination in , diastase activates to hydrolyze reserves, supplying glucose for embryonic growth and metabolic demands in the early stages of development.

History

Discovery

In 1833, French chemists Anselme Payen and Jean-François Persoz isolated diastase from germinating , commonly known as , marking it as the first to be discovered and purified in concentrated form. Working at a French sugar refinery, they extracted the substance from an aqueous infusion of malt flour, followed by precipitation using alcohol to obtain a white, powdery material that retained its activity. This isolation process mimicked traditional techniques used in and , where germinated naturally converts starches during . Payen and Persoz demonstrated diastase's function through experiments showing its ability to liquefy into dextrins and soluble sugars, even in small quantities. They observed this effect by mixing the extract with paste and heating it to temperatures between 65°C and 75°C, where the granules visibly broke down under microscopic examination, releasing their contents without requiring higher or acids typically used in industrial processing. This catalytic action accelerated the transformation far beyond what alone could achieve, highlighting diastase's role as an organic agent in biochemical reactions. The name "diastase" was chosen by Payen and Persoz to reflect the substance's primary effect: the separation (from the Greek diastasis, meaning "separation") of into its component parts, such as soluble sugars and . Their findings, detailed in a seminal , laid the groundwork for understanding enzymatic and its industrial potential in sugar production and .

Development of Enzyme Concept

Following the isolation of diastase from malt in , Anselme Payen and Jean-François Persoz advanced the understanding of biological by characterizing it as a heat-labile, soluble substance capable of converting to without requiring intact living cells, thereby positioning it as the first recognized non-living organic catalyst. This challenged prevailing vitalistic theories that attributed such processes solely to living organisms and laid the groundwork for viewing diastase as an extractable chemical agent rather than a vital force. In 1877, Wilhelm Kühne, a German physiologist, coined the term "" to encompass these unorganized ferments, drawing directly from examples like diastase and to denote proteinaceous catalysts that facilitate biochemical reactions outside of living yeast or cells. Kühne's nomenclature distinguished enzymes from organized ferments (living microbes) and emphasized their role as independent chemical entities, fostering a more precise conceptual framework for studying catalytic processes in and . The paradigm shifted decisively in 1897 with Eduard Buchner's experiments on cell-free yeast extracts, which demonstrated alcoholic without viable cells, confirming enzymes as non-vital, cell-produced catalysts and extending the principles established by diastase to broader metabolic phenomena. This breakthrough, awarded the 1907 , underscored the chemical autonomy of enzymes and eliminated lingering doubts about their dependence on protoplasmic . By the early , recognition grew that the original diastase preparation comprised a mixture of amylolytic enzymes, prompting purification efforts that isolated distinct components such as α-amylase and β-amylase, enabling detailed studies of their specificities. These developments, bolstered by James B. Sumner's 1926 crystallization of as the first pure —proving enzymes' proteinaceous nature—influenced analogous purifications of amylases and catalyzed progress in biochemistry and science, transforming enzymes into tools for industrial and scientific applications. Sumner's work shared the 1946 .

Biochemical Characteristics

Molecular Structure

Diastase enzymes, particularly α-amylase, are composed of a single polypeptide chain typically comprising 400–500 , with variations depending on the source . This primary structure includes conserved sequence domains essential for function, notably the catalytic domain A, which features a central (α/β)8 barrel motif surrounded by loops and additional structural elements. At the secondary and tertiary levels, α-amylase exhibits a characteristic fold with multiple α-helices and β-sheets forming three main domains: the catalytic (α/β)8 barrel in domain A, a β-sheet-rich domain B inserted between the third and fourth β-strands of the barrel, and a C-terminal antiparallel β-sheet domain C. Stability is enhanced by calcium-binding sites, often two to four per molecule, where Ca2+ ions coordinate with aspartate, glutamate, and residues to maintain the enzyme's conformation, particularly around the . Structural variations exist between bacterial and eukaryotic forms; bacterial α-amylases, such as those from Bacillus species, often lack certain eukaryotic-specific insertions in domain B and exhibit higher thermostability due to additional hydrophobic interactions, while eukaryotic enzymes like human salivary amylase (AMY1) contain 496 residues and five disulfide bonds that contribute to structural rigidity in the extracellular environment. β-Amylases, classified in glycoside hydrolase family GH14, consist of a single polypeptide chain typically comprising 450–550 amino acids, with a molecular weight around 55–60 kDa. They feature a central (β/α)8 barrel catalytic domain but lack the domain B insertion characteristic of GH13 α-amylases, instead having a simpler domain organization with an optional C-terminal starch-binding domain in some bacterial forms. While some β-amylases bind calcium non-catalytically for structural stability, it is not essential for activity, unlike in α-amylases.

Catalytic Mechanism

Diastase, primarily referring to α-amylase enzymes such as Taka-amylase A, operates via a retaining mechanism classified in family GH13, which proceeds through a double-displacement process involving a covalent glycosyl-enzyme intermediate. This mechanism relies on two key residues: an aspartate (Asp) acting as the and a glutamate (Glu) serving as the general acid/base catalyst, with an additional aspartate stabilizing the . In Taka-amylase A, these correspond to Asp206 (nucleophile), Glu230 (acid/base), and Asp297 (stabilizer), positioned within the cleft formed by the enzyme's (β/α)8 barrel structure. The catalytic cycle begins with the binding of or a related α-glucan substrate to the enzyme's , where the Glu230 residue protonates the oxygen of the α-1,4-glycosidic bond, facilitating the departure of the . Simultaneously, the Asp206 performs a direct attack on the anomeric carbon of the scissile bond, inverting the configuration to form a β-glycosyl-enzyme covalent intermediate and releasing the product (e.g., or ). In the second step, a is deprotonated by Glu230 (now acting as a base) and, aided by Asp297, attacks the anomeric carbon of the intermediate, resolving the oxocarbenium ion-like and hydrolyzing the bond to yield the α-anomeric product while regenerating the enzyme. This endo-acting process randomly cleaves internal α-1,4 linkages, producing shorter maltodextrins, , and as primary products. The simplified overall reaction catalyzed by diastase α-amylase can be represented as: (\ce[Starch](/page/Starch))n+\ceH2O→(\ce[Starch](/page/Starch))n−2+2 \ce[maltose](/page/Maltose)(\ce{[Starch](/page/Starch)})_n + \ce{H2O} \rightarrow (\ce{[Starch](/page/Starch)})_{n-2} + 2\ \ce{[maltose](/page/Maltose)} This equation illustrates the net of two α-1,4 bonds per molecule incorporated, though actual products vary due to the enzyme's multiple substrate-binding subsites. Optimal activity occurs at a pH of 6.7–7.0 and temperatures of 40–60°C, conditions under which the states of the catalytic residues are ideally balanced for efficient nucleophilic attack and . In contrast, in the diastase complex operates via an inverting mechanism in GH14, employing a single-displacement process with a carbonium ion-like . It relies on two glutamate residues acting as general acid and base catalysts, such as Glu186 (acid) and Glu380 (base) in , with additional residues like Asp101 and Thr342 stabilizing the . This exo-acting sequentially hydrolyzes α-1,4-glycosidic bonds from the non-reducing end of , releasing β-maltose units via a multiple-attack mechanism. The simplified overall reaction for β-amylase is: (\ceStarch)n+\ceH2O→(\ceStarch)n−1+\cemaltose(\ce{Starch})_n + \ce{H2O} \rightarrow (\ce{Starch})_{n-1} + \ce{maltose} Optimal activity for β-amylase occurs at a pH of 5.0–5.5 and temperatures of 50–65°C.

Natural Sources

In Plants

In plants, β-amylase is a key component of diastase activity, abundant in germinating seeds of cereals, where it facilitates the initial hydrolysis of starch into maltose and limit dextrins. This enzyme is stored in the endosperm in both free and bound forms, with the bound form comprising about 75% of the total β-amylase in dry barley grains, becoming active upon hydration during germination. In barley, β-amylase activity correlates strongly with diastatic power, a measure of the malt's starch-converting capacity, underscoring its central role in seed reserve mobilization. The physiological function of diastase centers on mobilizing stored reserves in the to supply fermentable sugars for the emerging seedling's energy needs during . This is triggered by , plant hormones released from the embryo, which induce the layer to synthesize and secrete β-amylase, enabling targeted degradation of granules. As progresses, β-amylase works synergistically with α-amylase to break down complex into simpler carbohydrates, supporting rapid growth until photosynthetic autonomy is achieved. High diastase activity is characteristic of cereals such as , , and , where it ensures efficient utilization. In rice grains treated with , diastase production peaks on the eighth day of , reaching up to 1546 units per gram of dry and enhancing conversion. serves as the primary source for commercial malt diastase, extracted from sprouted grains to harness its enzymatic potency for processing.

In Animals and Microorganisms

In animals, diastase activity is primarily manifested through α-amylase enzymes involved in . Salivary α-amylase, also known as ptyalin, is secreted by the salivary glands and initiates the of into and during oral mastication, functioning optimally at a neutral . This process begins the breakdown of complex in the before the partially digested bolus reaches the , where acidic conditions temporarily halt further activity. Pancreatic α-amylase, released into the via the , resumes and completes digestion in the by cleaving remaining oligosaccharides into and glucose units, facilitating nutrient absorption. In humans, serum amylase levels, which reflect pancreatic and salivary contributions, typically range from 30 to 110 U/L in healthy individuals. Microorganisms also produce diastase-like α-amylases for degradation, often extracellularly to support nutrient acquisition in their environments. Bacteria such as secrete α-amylase to hydrolyze external into fermentable sugars, enabling efficient carbon utilization during growth. Similarly, fungi like generate high levels of this , which plays a crucial role in breakdown during processes, such as those used in production. From an evolutionary perspective, duplications of the human AMY1 gene, encoding salivary α-amylase, have been associated with adaptations to starch-rich diets, with higher copy numbers observed in populations historically reliant on agriculture and domesticated crops. This genetic variation enhances starch digestion efficiency, reflecting selective pressures from dietary shifts.

Applications and Significance

Industrial Uses

Diastase, primarily referring to α-amylase enzymes derived from microbial sources, plays a key role in the by hydrolyzing into fermentable sugars. In , diastase facilitates during , converting starches into and dextrins to support and improve alcohol yield. In baking, it is added to dough to generate simple sugars that enhance , resulting in improved volume, texture, and by reducing . For syrup manufacturing, immobilized diastase enzymes enable efficient liquefaction in the production of , where is first broken down into before . Beyond , diastase finds applications in several other sectors due to its starch-degrading properties. In textile , it removes starch-based agents from yarns, preparing fabrics for and finishing while minimizing environmental impact compared to chemical methods. In production, diastase modifies for surface coating, reducing to improve paper strength and printability. For production, it supports by saccharifying starch feedstocks like corn, contributing to higher conversion efficiencies in industrial-scale bioethanol processes. Industrial diastase is predominantly produced via microbial fermentation using bacteria such as Bacillus species or fungi like Aspergillus oryzae, yielding up to 159,520 U/g dry substrate under optimized conditions. These enzymes exhibit optimal activity at 50–70°C and pH 5–7, aligning with process requirements for starch hydrolysis in large-scale operations.

Clinical and Diagnostic Uses

Diastase serves as a digestive aid in pharmaceuticals, particularly fungal-derived forms, to enhance breakdown in conditions such as , , , and . Oral supplements provide exogenous activity to hydrolyze starches, alleviating symptoms like , , and while improving nutrient uptake. These preparations are often combined with and in enteric-coated capsules, with dosing typically at 18,000–25,000 U per meal, adjusted based on fat intake and individual response. Historically, diastase was incorporated into early 20th-century proprietary formulas to predigest starches, addressing immature in bottle-fed babies and reducing risks. In , diastase is employed as a in periodic acid-Schiff (PAS) protocols to selectively remove from tissue sections. This distinguishes from other PAS-positive mucosubstances, aiding diagnoses of glycogen storage diseases, fungal infections (e.g., via capsule ), and various pathologies in liver, , and muscle tissues.

References

  1. https://www.sciencedirect.com/topics/biochemistry-genetics-and-molecular-biology/diastase
  2. https://jamanetwork.com/journals/jama/fullarticle/246007
  3. https://beer-studies.com/en/world-history/Brewery-scientific-age/Malting-diastases
  4. https://www.sciencedirect.com/science/article/pii/S0040402006016000
  5. https://www.sciencedirect.com/science/article/pii/S0308814615013941
  6. https://www.beerandbrewing.com/dictionary/6JW1tWTr0U
  7. https://pmc.ncbi.nlm.nih.gov/articles/PMC10891418/
  8. https://www.sciencedirect.com/science/article/pii/B9780702042263000123
  9. https://ijcrt.org/papers/IJCRT2308260.pdf
  10. https://www.etymonline.com/word/diastase
  11. https://www.genome.jp/dbget-bin/www_bget?ec:3.2.1.1
  12. https://www.genome.jp/dbget-bin/www_bget?ec:3.2.1.2
  13. https://scienceinschool.org/article/2007/enzymes/
  14. https://www.sciencedirect.com/topics/biochemistry-genetics-and-molecular-biology/alpha-amylase
  15. https://www.sciencedirect.com/science/article/abs/pii/S014486170400462X
  16. https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/beta-amylase
  17. https://link.springer.com/article/10.1007/s00217-020-03657-y
  18. https://www.ncbi.nlm.nih.gov/books/NBK557738/
  19. https://pmc.ncbi.nlm.nih.gov/articles/PMC3784079/
  20. https://pmc.ncbi.nlm.nih.gov/articles/PMC7756376/
  21. https://www.nobelprize.org/prizes/chemistry/1946/sumner/facts/
  22. https://www.uniprot.org/uniprotkb/P04746/entry
  23. https://pmc.ncbi.nlm.nih.gov/articles/PMC91620/
  24. https://www.sciencedirect.com/science/article/abs/pii/0006291X85917024
  25. https://academic.oup.com/mbe/article/18/1/38/982926
  26. https://pubmed.ncbi.nlm.nih.gov/2207069/
  27. https://www.nature.com/articles/srep23126
  28. https://www.uniprot.org/uniprotkb/P0DUB6/entry
  29. https://pubmed.ncbi.nlm.nih.gov/22390166/
  30. https://pmc.ncbi.nlm.nih.gov/articles/PMC4963412/
  31. https://www.uniprot.org/uniprotkb/P10538/entry
  32. https://www.ebi.ac.uk/thornton-srv/m-csa/entry/436/
  33. https://www.rcsb.org/structure/1B9Z
  34. https://www.cazypedia.org/index.php/Glycoside_Hydrolase_Family_13
  35. https://www.ebi.ac.uk/thornton-srv/m-csa/entry/397/
  36. https://pmc.ncbi.nlm.nih.gov/articles/PMC11535007/
  37. https://beersmith.com/blog/2021/10/02/enzymes-in-beer-alpha-and-beta-amylase/
  38. https://pmc.ncbi.nlm.nih.gov/articles/PMC34988/
  39. https://www.sciencedirect.com/science/article/pii/S0733521001903674
  40. https://link.springer.com/article/10.1007/BF02922990
  41. https://www.annualreviews.org/doi/pdf/10.1146/annurev.pp.24.060173.003035
  42. https://www.researchgate.net/publication/248588463_Variation_of_Beta_Amylase_Activity_in_Barley_as_Affected_by_Cultivar_and_Environment_and_its_Relation_to_Protein_Content_and_Grain_Weight
  43. https://pdfs.semanticscholar.org/4479/b9f5ec6839027ac571a6878b3003559c0cac.pdf
  44. https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/malting-barley
  45. https://www.ncbi.nlm.nih.gov/books/NBK544242/
  46. https://pmc.ncbi.nlm.nih.gov/articles/PMC6825871/
  47. https://www.ncbi.nlm.nih.gov/books/NBK559273/
  48. https://pmc.ncbi.nlm.nih.gov/articles/PMC3769773/
  49. https://pmc.ncbi.nlm.nih.gov/articles/PMC8094467/
  50. https://www.science.org/doi/10.1126/science.adn0609
  51. https://www.nature.com/articles/s41586-024-07911-1
  52. https://pmc.ncbi.nlm.nih.gov/articles/PMC5956270/
  53. https://www.sciencedirect.com/science/article/abs/pii/S0032959202001504
  54. https://www.sciencedirect.com/science/article/pii/S0717345825000132
  55. https://pmc.ncbi.nlm.nih.gov/articles/PMC4923703/
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