Elementary Processes in the Interaction of Serine Protease with a Possible Transition State Analog Subtilisin-Benzeneboronic Acid System1
1975; Oxford University Press; Volume: 78; Issue: 3 Linguagem: Inglês
10.1093/oxfordjournals.jbchem.a130947
ISSN1756-2651
AutoresHiroshi Nakatani, Yukiko Uehara, Keitarō Hiromi,
Tópico(s)Protein Structure and Dynamics
ResumoThe 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.
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