Microsomal methionine aminopeptidase: properties of the detergent-solubilized enzyme.
A methionine aminopeptidase (MAP) found in rat liver microsomes behaves as membrane-bound enzyme. Triton-solubilized MAP when chromatographed on DEAE-cellulose columns was separated from other microsomal arylamidases. The enzyme hydrolyzes N-terminal methionine from methionyl-lysyl-bradykinin (Met-Lys-Arg-Pro-Pro-Gly-Phe-Ser-Pro-Phe-Arg) being then characterized as a typical aminopeptidase. It also shows preferential arylamidase activity upon Met-2-naphthylamide. MAP was activated by 2-mercaptoethanol and inhibited by p-hydroxymercuribenzoate. Contrarily to other well characterized aminopeptidases, MAP was not affected by EDTA, puromycin or bestatin. Altogether these data suggest that MAP is a unique microsomal enzyme distinct from other previously described aminopeptidases. It could be involved in the removal of methionine from nascent peptides during protein synthesis.
D000577:Amides; D000626:Aminopeptidases / Q000032:analysis*; D000818:Animals; D001920:Bradykinin / Q000031:analogs & derivatives / Q000494:pharmacology; D002462:Cell Membrane / Q000201:enzymology; D002848:Chromatography, DEAE-Cellulose; D004789:Enzyme Activation / Q000187:drug effects; D006902:Hydroxymercuribenzoates / Q000494:pharmacology; D008623:Mercaptoethanol / Q000494:pharmacology; D063208:Methionyl Aminopeptidases; D008862:Microsomes, Liver / Q000201:enzymology*; D017830:Octoxynol; D010447:Peptide Hydrolases / Q000494:pharmacology; D011092:Polyethylene Glycols / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D012995:Solubility; D013997:Time Factors
D000577:Amides; D006902:Hydroxymercuribenzoates; D011092:Polyethylene Glycols; C018103:bradykinin, Met-Lys-; D008623:Mercaptoethanol; D017830:Octoxynol; D010447:Peptide Hydrolases; D000626:Aminopeptidases; D063208:Methionyl Aminopeptidases; D001920:Bradykinin