N‐terminal acetyl group is essential for the inhibitory function of carboxypeptidase Y inhibitor (IC)

FEBS Letters

Kondo, Takahiro¹  Hayashi, Rikimaru¹  Mima, Joji¹ 

[1]Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan

关键词: Carboxypeptidase inhibitor;    Carboxypeptidase Y;    N-terminal acetylation;    Inhibition mechanism;    Bz-Tyr-pNA;    N-benzoyl-L-tyrosine-p-nitroanilide;    CBZ;    benzyloxycarbonyl;    CPY;    carboxypeptidase Y;    IC;    carboxypeptidase Y inhibitor;    PCMB;    p-chloromercuribenzoic acid;    PMSF;    phenylmethylsulfonyl fluoride;    unaIC;    unacetylated form of carboxypeptidase Y inhibitor;   

DOI  :  10.1016/S0014-5793(02)03676-1

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Carboxypeptidase Y (CPY) inhibitor, I^C, a yeast cytoplasmic inhibitor in which the N-terminal amino acid is acetylated, was expressed in Escherichia coli and produced as an unacetylated form of I^C (unaI^C). Circular dichroism and fluorescence measurements showed that unaI^C and I^C were structurally identical and produce identical complexes with CPY. However, the K _i values for unaI^C for anilidase and peptidase activity of CPY were much larger, by 700- and 60-fold, respectively, than those of I^C. The reactivities of phenylmethylsulfonyl fluoride and p-chloromercuribenzoic acid toward the CPY–unaI^C complex were considerably higher than those toward the CPY–I^C complex. Thus, the N-terminal acetyl group of I^C is essential for achieving a tight interaction with CPY and for its complete inactivation.

【 授权许可】

Unknown