The effect of alpha2-macroglobulin from bovine serum on bovine alpha-chymotrypsin.
Bovine alpha2-globulin contains a protein which increases the activity of bovine alpha-chymotrypsin against synthetic substrates. The active protein fraction migrates slowly on polyacrylamide gel electrophoresis, so it was named slow alpha2-globulin (Salpha2). The fraction was isolated from bovine serum and purified. Its sedimentation constant S20 was 18.5 S. It was thus identified with the alpha2-macroglobulin (alpha2M). By kinetic studies, the dissociation constant of the alpha-chymotrypsin-alpha2 M complex was calculated to be of the order of 10(-7) l/mol. The purified alpha2 M was shown to bind alpha-chymotrypsin at a definite rate. If the binding ratio was assumed to be 1:2, the molecular weight was calculated to be about 8 X 10(5).
D000818:Animals; D002417:Cattle; D002918:Chymotrypsin / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D004789:Enzyme Activation; D007700:Kinetics; D008259:Macroglobulins / Q000378:metabolism*; D008433:Mathematics; D008970:Molecular Weight
D008259:Macroglobulins; D002918:Chymotrypsin