Covalent and non‐covalent interaction of chymotrypsin with α2‐macroglobulin

• Published in: FEBS letters 1987-06, Vol.217 (1), p.101-105
• Main Authors: Pochon, François, Tourbez, Martine, Favaudon, Vincent, Delain, Etienne
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; Chymotrypsin; Covalent interaction; Electrophoresis; FITC, fluorescein isothiocyanate; Fundamental and applied biological sciences. Psychology; Hepes, N-(2-hydroxyethyl)piperazine-N′-2-ethanesulfonate; I-AEDns, N-(iodoacetylaminoethyl)-5-naphthylamine-1-sulfonate; Interactions. Associations; Intermolecular phenomena; Molecular biophysics; Non-covalent interaction; α2-Macroglobulin; α2M, α2-macroglobuIin
• ISSN: 0014-5793; 1873-3468
• DOI: 10.1016/0014-5793(87)81251-6

The pattern of covalent crosslinking between human α2‐macroglobulin (α2M) and chymotrypsin has been investigated by chromatography and polyacrylamide gel electrophoresis in denaturing medium. Reaction with a single mol of chymotrypsin per mol α2M results in the formation of a 95% covalent 1:1 chymotrypsin‐α2M complex and in the proteolytic cleavage of both 180 kDa monomers in one α2M subunit. Proteolytic cleavage in the other α2M subunit requires the presence of a second mol of chymotrypsin; part (20%) of the protease in the 2:1 chymotrypsin‐α2M complex thus formed appears to be non‐covalently bound to the α2M chains. Covalent binding is abolished when the reaction of α2M with the protease is carried out in the presence of hydroxylamine. A single mol of the protease is then able to cleave all four 180 kDa monomers in α2M.