Self-association of diisopropylphosphoryl-alpha-chymotrypsin: the involvement of active site of the enzyme in its self-association behaviour.
The self-association of diisopropylphosphoryl(DIP)-alpha-chymotrypsin is studied in order to find out whether the active site of the enzyme is involved in its self-association behaviour or not. Sedimentation coefficient as well as the weight-average (Archibald) molecular weight data are obtained as a function of concentration using an analytical ultracentrifugation technique. The analysis indicated that the experimental data fits the model of indefinite self-association. The comparison of the data with earlier data on alpha-chymotrypsin revealed that after the modification at the active site, the association constant for the self-association is reduced by about 47%, and the system deviated from ideality. Results showed further that Ser-195, at the active site, appears to be involved in the self-association behaviour of alpha-chymotrypsin; however, the participation of other groups at the active site is also implicated.
Murthy
B S
BS
Centre for Cellular and Molecular Biology, Hyderabad, India.
Pandit
M W
MW
D001665:Binding Sites; D002499:Centrifugation, Density Gradient; D002918:Chymotrypsin / Q000737:chemistry / Q000378:metabolism*; D007700:Kinetics; D008970:Molecular Weight; D009943:Organophosphorus Compounds / Q000737:chemistry / Q000378:metabolism
D009943:Organophosphorus Compounds; D002918:Chymotrypsin; C007444:diisopropylphosphoryl-alpha-chymotrypsin