Bacterial β-peptidyl aminopeptidases: on the hydrolytic degradation of β-peptides

The special chemical and biological features of β-peptides have been investigated intensively during recent years. Many studies emphasize the restricted biodegradability and the high metabolic stability of this class of compounds. β-Peptidyl aminopeptidases form the first family of enzymes that hydrolyze a variety of short β-peptides and β-amino-acid-containing peptides. All representatives of this family were isolated from Gram-negative bacteria. The substrate specificities of the peptidases vary greatly, but the enzymes have common structural properties, and a similar reaction mechanism can be expected. This review gives an overview on the β-peptidyl aminopeptidases with emphasis on their biochemical and structural properties. Their possible physiological function is discussed. Functionally and structurally related enzymes are compared to the β-peptidyl aminopeptidase