Membrane-bound alanine aminopeptidase from Acinetobacter calcoaceticus. 4. Amino acid chloromethyl ketones as pH-dependent, substrate-derived inhibitors of cysteine protease
Jahreis, G.; Aurich, H.
Biomedica Biochimica Acta 50(9): 1043-1049
1991
ISSN/ISBN: 0232-766X PMID: 1686704 Document Number: 373805
The alanine aminopeptidase (AAP) from A. calcoaceticus is a metal-ion-dependent cysteine protease bound to the inner membranes of the cells. Amino acid chloromethyl ketones are highly specific inhibitors of the enzyme. The AAP is inhibited at pH 7.5 (pH-optimum) by mixed-type inhibition. A competitive inhibition type results if the pH value is decreased to 6.2. In contrast, the inhibition of the AAP by substrate-derived chloromethyl ketones is of the irreversible type at pH 8.25.