Unique cleavage specificity of ‘prohormone thiol protease’ related to proenkephalin processing

FEBS Letters

Hook, Vivian Y.H.¹  Azaryan, Anahit V.¹ 

[1] Department of Biochemistry, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA

关键词: Prohormone processing;    Cysteine protease;    Proenkephalin;    Neuropeptide;    Peptide-MCA;    PTP;    prohormone thiol protease;    MCA;    methylcoumarinamide;    AMC;    7-aimno-4-methylcoumarin;    APM;    aminopeptidase M;    -CHN2;    diazomethane;    -CH2Cl;    chloromethylketone;    Z-;    carboxybenzoyl;    Boc-;    tert-butoxycarbonyl;    Bz-;    benzoyl;    DTT;    dithiothreitol;    PC;    proprotein convertase;   

DOI  :  10.1016/0014-5793(94)80456-7

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

‘Prohormone thiol protease’ (PTP) represents the major enkephalin precursor processing activity in chromaffin granules. In this study, cleavage specificity of PTP for paired basic and monobasic residues was examined with a series of model peptide-MCA (-methylcoumarinamide) substrates. Monobasic peptides were cleaved at the COOH- and NH₂-terminal sides of the single basic residue. Dibasic peptides, however, were preferentially cleaved at the NH₂-terminal side of the pair, or between the two basic residues, with low cleavage at the COOH-terminal side of the pair. Inhibition by the peptide inhibitor (d-Tyr)-Glu-Phe-Lys-Arg-CH₂Cl provided further evidence for ptp's specificity for the dibasic Lys-Arg site. Inhibition by Z-Leu-Val-Gly-CHN₂; and Z-Arg-Leu-Val-Gly-CHN₂; suggests involvement of Val-Gly in substrate binding to PTP; these two cystatin C-related inhibitors also indicate PTP as a cysteine protease. These results demonstrate PTP's unique cleavage specificity that differs from other processing endopeptidases, including the subtilisin-related proprotein convertases, PC1/PC3, and PC2, as well as the pituitary proopiomelanocortin-converting enzyme, PCE. This study provides further evidence for PTP as a novel prohormone processing enzyme that belongs to the class of cysteine proteases.

【 授权许可】

Unknown