Elementary processes in the interaction of serine protease with a possible transition state analog. Subtillisin-benzeneboronic acid system.
The interaction of benzeneboronic acid(BBA), a possible transition state analog, with subtilisin BPN' [EC 3.4.21.14] was studied by the temperature-jump method at various pH's, temperatures and in D2O as well as H2O. From analysis of the concentration dependence of the relaxation times, it was suggested that the subtillsin-BBA interactions consist of at least two elementary steps, a fast bimolecular association followed by a slow unimolecular process. Similar concentration dependence was observed at pH 6.1-6.7 at 25degrees. However, in D2O the reciprocal relaxation times generally decreased compared to those in H2O and became concentration-independent below pD 6.5. The relaxation times were influenced considerably by the temperature. From these results, the slow unimolecular process was assigned to the trigonal-tetrahedral interconversion of BBA at the active site of the enzyme.
D001554:Benzene; D001665:Binding Sites; D001897:Boronic Acids; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008433:Mathematics; D010447:Peptide Hydrolases / Q000378:metabolism; D011485:Protein Binding; D013381:Subtilisins / Q000378:metabolism; D013696:Temperature; D013816:Thermodynamics
D001897:Boronic Acids; D010447:Peptide Hydrolases; D013381:Subtilisins; D001554:Benzene