Albumin

Albumin is a family of globular proteins, the most common of which are the serum albumins. All of the proteins of the albumin family are water-soluble, moderately soluble in concentrated salt solutions, and experience heat denaturation. Albumins are commonly found in blood plasma and differ from other blood proteins in that they are not glycosylated. Substances containing albumins are called albuminoids.

A number of blood transport proteins are evolutionarily related in the albumin family, including serum albumin, alpha-fetoprotein, vitamin D-binding protein and afamin. This family is only found in vertebrates.

Albumins in a less strict sense can mean other proteins that coagulate under certain conditions. See § Other albumin types for lactalbumin, ovalbumin and plant "2S albumin".

Albumins in general are transport proteins that bind to various ligands and carry them around. Human types include:

The four canonical human albumins are arranged on chromosome 4 region 4q13.3 in a tandem manner.

Albumins found in animals can be divided into six subfamilies by phylogeny. The Vitamin-D binding proteins occupy families 1–3. The other albumins are mixed among each other in families 4–6. ECM1 is in family 6.

In addition to their medical use, serum albumins are valued in biotechnology. Bovine serum albumin is usually used, although versions from humans and genetically modified rice are also used to reduce animal cruelty.

A few other proteins are also sometimes called albumins. They are not in the same family as vertebrate albumins: