Mechanism of inhibition of papain by chicken egg white cystatin

FEBS Letters

Laber, Bernd¹  Machleidt, Werner¹  Assfalg-Machleidt, Irmgard¹  Thiele, Ulrich¹  Bode, Wolfram¹  Wiegand, George¹  Kos, Janko¹  Turk, Vito¹  Esterl, Anna¹ 

[1] Institut für Physiologische Chemie, Physikalische Biochemie und Zellbiologie der Universität München, Goethestrasse 33, D-8000 München 2, FRG

关键词: Cystatin;    Papain;    Cysteine proteinase;    Enzyme inhibitor;    Inhibitor mechanism;    (Chicken egg white);    E-64;    1-(trans-epoxysuccinyl-L-leucylamino)-4-guanidinobutane;    FPLC;    fast protein liquid chromatography;   

DOI  :  10.1016/0014-5793(89)80135-8

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

N-terminally truncated forms of chicken egg white cystatin and its cyanogen bromide fragments were isolated and assayed for inhibition of papain. Truncated forms beginning with Gly-9 and Ala-10 had a 5000-fold lower affinity for papain than the two isoelectric forms (pI=6.5 and 5.6) of the full-length inhibitor (K _i=6 pM and 7 pM) or a truncated form beginning with Leu-7 (K _i=6 pM), indicating the outstanding importance of one or two residues preceding conserved Gly-9 for binding. A weak inhibition of papain (K _i=900 nM) was exhibited by the intermediate cyanogen bromide fragment (residues 30–89) containing the chicken cystatin QLVSG variation of the QVVAG segment which is conserved in almost all members of the cystatin superfamily. The obtained affiffity data provide independent evidence for the validity of the proposed docking model of a chicken cystatin-papain complex [(1988) EMBO J. 7, 2593–2599].

【 授权许可】

Unknown