Open AccessHuman‐Liver Alanine Aminopeptidase
Author(s) -
STARNES Willis L.,
SZECHIŃSKJ Jacek,
BĚHAL Francic J.
Publication year - 1982
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1982.tb06601.x
Subject(s) - cloxacillin , chemistry , biochemistry , enzyme , alanine , penicillin , sephadex , hydrolysis , amino acid , antibiotics
Human liver alanine aminopeptidase (EC 3.4.11.14; l ‐α‐aininoacyl‐peptide hydrolasc) catalyzes the stepwisc hydrolysis of mcthionyl‐lysyl‐bradykinin to yield methionine, lysine, and the limit nonapeptide, bradykinin. which is resistant to further hydrolytic cleavage by this enzyme. Alanine aminopeptidase also catalyzes the hydrolysis of various neutral amino acid β‐naphthylamide This enzyme cleaves N‐terminal arginyl residues unless the adjacent penultimate residue is proline as is the case for bradykinin. The properties are consistent with requirements of a kinin converting enzyme. Human alanine aminopeptidase activity is reduced by several β‐lactani antibiotics, with the cloxacillin, oxacillin. and inethicillin K i values being 0.51 mM, I.6 mM. and 2.4mM respectively. Our experiments with radioactively labelled penicillin indicate that two moles of antibiotic are bound per mole of enzyme. Neither chromatography of the penicillin‐treatcd enzymc on G‐25 Sephadex, treatment penicillin‐Ci‐treated enzyme with penicillinase, nor extensive dilution of cloxacillin‐treated enzyme diminished the degree of inactivation produced. Inhibition was obtained with 6‐aminopenicillanic acid, which indicated that penicillin nucleus itself was being bound, but substitutions, as in cloxacillin, could enhance the binding.