High‐molecular‐weight kininogen binds two molecules of cysteine proteinases with different rate constants

FEBS Letters

Cazzulo, Juan Jose¹  Johansson, Gunnar³  Björk, Ingemar²  Turk, Boris²  Turk, Vito⁴  Stoka, Veronika⁴ 

[1] Instituto de Investigaciones Bioquimicas ‘Luis F. Leloir’, Fundacion Campomar-CONICET, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina;Department of Veterinary Medical Chemistry, Swedish University of Agricultural Sciences, The Biomedical Center, Upssala, Sweden;Department of Biochemistry, Uppsala University, The Biomedical Center, Uppsala, Sweden;Department of Biochemistry and Molecular Biology, Jozef Stefan Institute, Jamova 39, 1111 Ljubljana, Slovenia

关键词: Kininogen;    Cathepsin;    Cystatin;    Cysteine proteinase;    Kinetics;    -AMC;    aminomethyl coumaryl amide;    HK;    high-molecular-weight Lk;    low-molecular-weight kininogen;    Z-;    benzoyloxycarbonyl;   

DOI  :  10.1016/0014-5793(96)00611-4

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Fluorescence titrations showed that high-molecular-weight kininogen binds two molecules of papain, cruzipain and cathepsin S with high affinity. The 2:1 binding stoichiometry was confirmed by stopped-flow kinetic measurements of papain binding, which also revealed that the two sites bind the enzyme with different association rate constants (k _ass,1 = 23.0 × 10⁶ M⁻ s⁻¹ and k _ass2, = 3.4 × 10⁶ M⁻¹s⁻¹. As for low-molecular-weight kininogen, comparison of these kinetic constants with previous data for intact low- and high-molecular-weight kininogen and the separated domains indicated that the faster-binding site is also the tighter-binding site and is that of domain 3, whereas the slower-binding, lower-affinity site is on domain 2. The results further demonstrate that there is no appreciable steric interference between the two domains or by the kininogen light chain in the binding of proteinases. Similarly, the binding of kininogen via its light chain to a surface, as indicated by the binding to the model surface, heparin, did not affect the inhibitory properties of kininogen. The M _r of high-molecular-weight kininogen was determined to be 83 500 by sedimentation equilibrium measurements, in agreement with the value calculated from amino acid sequence and carbohydrate analysis.

【 授权许可】

Unknown