Enkephalin hydrolysis by human serum biotinidase

• Published in: Biochimica et biophysica acta Vol. 1074; no. 3; pp. 433 - 438
• Main Authors: Oizumi, Jun, Hayakawa, Kou
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 06.08.1991; Elsevier
• Subjects: Amidohydrolases - antagonists & inhibitors; Amidohydrolases - blood; Amidohydrolases - metabolism; Amino Acid Sequence; Aminopeptidase; Analytical, structural and metabolic biochemistry; Biological and medical sciences; Biotinidase; Dynorphins - metabolism; Electrophoresis, Polyacrylamide Gel; Endorphins - metabolism; Enkephalins - metabolism; Enzymes and enzyme inhibitors; Exo-peptidase; Fundamental and applied biological sciences. Psychology; Humans; Hydrolases; Hydrolysis; Kinetics; Lysine - analogs & derivatives; Lysine - pharmacology; Molecular Sequence Data; Opioid neuropeptide; Substrate Specificity; Vitamins - pharmacology; OPA; BCA; Biotinidase; PAMSF; Biocytin; PCMB; DFP; Opioid neuropeptide; RP-HPLC; BPAB; BSA; SDS-PAGE; PMSF; p I; ME; Aminopeptidase; Exo-peptidase; HPLC; Hydrolysis; Enzymatic activity; Enzyme; Substrate specificity; Peptide hormone; Enkephalin; Inhibition; Kinetic parameter; Neuropeptide
• ISSN: 0304-4165; 0006-3002; 1872-8006
• DOI: 10.1016/0304-4165(91)90096-Y

Purified human serum biotinidase exhibited amino-exo-peptidase activity. Enkephalins and dynorphin A (less than 10-mer) seemed to be the most appropriate substrates among various physiological peptides in terms of the k cat/ K m values. Similar k cat/ K m values were obtained for both biocytin (biotinyllysine) and these opioid-neuropeptides. Neuro-oligo-peptides ranging from 2-mer to 18-mer were hydrolyzed. The presence of amino group at the carboxyl terminal position increased the k cat/ K m value by decreasing the K m value. The results of inhibition studies using various kinds of antibiotic inhibitors, metals, and chelating agents indicated that enkephalin hydrolysis was mediated by the peptide-hydrolyzing center probably containing Zn ions. This aminopeptidase activity was uniquely inhibited by a vitamin of biocytin. The reason for the high content of biotinidase activity in serum may be related to the binary function of this enzyme; i.e., biocytin hydrolyzing amidase and enkephalin hydrolyzing aminopeptidase functions.