Direct kinetics of bait region cleavage of α‐2‐macroglobulin by a rapid quenching method

FEBS Letters

Shibuya, Nozomu¹  Ikai, Atsushi¹ 

[1] Laboratory of Biodynamics, Tokyo Institute of Technology, Nagatsuta, Midoriku, Yokohama 227, Japan

关键词: α-2-Macroglobulin;    Bait region cleavage;    Rapid quenching method;    SDS-PAGE;    sodium dodecyl sulfate-polyacrylamide gel electrophoresis;    α2M;    α-2-macroglobulin;   

DOI  :  10.1016/0014-5793(93)81765-R

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The rate of bait region cleavage of human α-2-macroglobulin by chymotrypsin was determined by a rapid quenching method under conditions where the bimolecular encounter between the two reactants was not rate-limiting. α₂M was first mixed with a 30 molar excess of chymotrypsin in a sequential stopped-flow apparatus and after programmed time intervals the activity of chymotrypsin was quenched with 1 N HCl. The fraction of uncleaved subunits was quantitated by SDS-PAGE under reducing conditions. The result indicated that the bait region cleavage proceeded following a two-exponential decay curve with respective rate constants of k ₁ = 40 s⁻¹ and k ₂ = 2 s⁻¹.

【 授权许可】

Unknown