title: Temperature-jump studies on benzeneboronic acid-serine protease interactions.  Subtilisin and alpha-chymotrypsin.
abstract: The interactions of benzeneboronic acid (BBA) as a transition state analog with subtilisin (EC 3.4.21.4) and with alpha-chymotrypsin (EC 3.4.21.1) were investigated kinetically by the temperature-jump method using pH indicators.  For both enzymes, the concentration dependence of the relaxation time was consistent with a two-step mechanism involving a fast bimolecular association followed by a slow, unimolecular process.  The possibility of a trigonal-tetrahedral interconversion of BBA at the active site of the enzyme is discussed.
mesh_terms: D001554:Benzene; D001665:Binding Sites; D001897:Boronic Acids; D055598:Chemical Phenomena; D002621:Chemistry; D002918:Chymotrypsin; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008433:Mathematics; D013381:Subtilisins; D013696:Temperature
chemical_list: D001897:Boronic Acids; D013381:Subtilisins; D002918:Chymotrypsin; D001554:Benzene