Amidase

Amidases (also: amidohydrolases ) are in enzymology, a branch of biochemistry, enzymes that catalyze a chemical reaction for the cleavage of amide bonds. The enzymes form a subfamily of the hydrolases. They fulfill important functions in all living things.

Catalyzed reactions

A monocarboxylic acid amide reacts with water under the influence of an amidase to a monocarboxylic acid and ammonia or the ammonium salt of the monocarboxylic acid:

Also some secondary amides are hydrolyzed by amidases, but here is shown the stability of the amide bonds, most, which can not be divided as follows:

In the particular case of a peptide bond is called the cleaving enzyme peptidase, these are no longer formally to the amidases.

Cyclic amide, such as lactams, cleaved by lactamases, which are also part of the amidases:

Amidases in human

In humans, several dozen amidases have been identified that meet all important functions, including ceramidases histone deacetylases and sirtuins. More important individual enzymes of this group are the Arylformamidase that biotinidase, the glutaminase and the Pantetheinase.

Pathology

Of eight amidases human polymorphisms are known, which can lead to rare genetic diseases.

Technical application for the resolution

The enzyme L- acylase is also one of the amidases. Finds industrial application in the resolution of amino acids. From the acetylation of the amino group of the racemic amino acid DL-methionine with acetic anhydride resulting N-acetyl -DL- methionine. Enantiospecific the acetyl group of N-acetyl- L- methionine is cleaved then the catalytic effect of the L- acylase is produced acetic acid and L-methionine. N- acetyl-D -methionine is unchanged. This procedure is also called kinetic resolution. According to the same principle of separation is the resolution of many other α -amino acids is possible.