Basic amino acids preferring broad specificity aminopeptidase from human erythrocytes.
An aminopeptidase hydrolyzing 2-naphthylamides of Lys, Arg, Leu, Met, Phe and Tyr, as well as different di- to tridecapeptides, was purified from the cytosol of human erythrocytes. The enzyme showed preference for Lys and Arg at N-terminus, as proline and D-amino acids were nonpermissive at P1' site. Higher affinity for oligopeptides than for aminoacyl naphthylamides was observed. Among the substrates were Lys-bradykinin, angiotensin III, thymopentin and enkephalins. Aminopeptidase was shown to be a monomeric protein of M(r) approximately 110000 and of pI approximately 4.8, activated by Co2+ and inhibited by EDTA, pHMB, amastatin, bestatin and puromycin. The isolated enzyme could be classified as cytosolic, Lys(Arg) preferring, broad specificity aminopeptidase.
Abramić
M
M
Dept. Organic Chemistry and Biochemistry, Rudjer Bosković Institute, Zagreb, Croatia.
Vitale
L
L
D000595:Amino Acid Sequence; D000596:Amino Acids / Q000378:metabolism*; D000626:Aminopeptidases / Q000097:blood* / Q000302:isolation & purification; D003600:Cytosol / Q000201:enzymology; D004912:Erythrocytes / Q000201:enzymology*; D006801:Humans; D007525:Isoelectric Focusing; D007700:Kinetics; D008969:Molecular Sequence Data; D008970:Molecular Weight; D013379:Substrate Specificity
D000596:Amino Acids; D000626:Aminopeptidases