Abstract
The variation of kinetic parameters of beta-glucosidase from Trichoderma reesei QM 9414 with pH was used to gain information about the chemical mechanism of the reaction catalysed by this enzyme. The pH-dependence of Vmax. and Vmax./Km for p-nitrophenyl beta-D-glucopyranoside showed that a group with a pK value of 4.3 must be unprotonated and a group with a pK value of 5.9 must be protonated for activity. Temperature and solvent-perturbation studies indicated that these groups are a histidine residue and a carboxy group respectively. Profiles of pKi for maltose as competitive inhibitor showed that binding is prevented when a group on the enzyme with a pK value of 4.5 becomes protonated.
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- Blake C. C., Johnson L. N., Mair G. A., North A. C., Phillips D. C., Sarma V. R. Crystallographic studies of the activity of hen egg-white lysozyme. Proc R Soc Lond B Biol Sci. 1967 Apr 18;167(1009):378–388. doi: 10.1098/rspb.1967.0035. [DOI] [PubMed] [Google Scholar]
- Clarke A. J. Chemical modification of a beta-glucosidase from Schizophyllum commune: evidence for essential carboxyl groups. Biochim Biophys Acta. 1990 Sep 3;1040(2):145–152. doi: 10.1016/0167-4838(90)90069-r. [DOI] [PubMed] [Google Scholar]
- Cleland W. W. Determining the chemical mechanisms of enzyme-catalyzed reactions by kinetic studies. Adv Enzymol Relat Areas Mol Biol. 1977;45:273–387. doi: 10.1002/9780470122907.ch4. [DOI] [PubMed] [Google Scholar]
- Cleland W. W. The use of pH studies to determine chemical mechanisms of enzyme-catalyzed reactions. Methods Enzymol. 1982;87:390–405. doi: 10.1016/s0076-6879(82)87024-9. [DOI] [PubMed] [Google Scholar]
- Donsimoni R., Legler G., Bourbouze R., Lalegerie P. Study of beta-glucosidase from Helix pomatia by active site-directed inhibitors. Enzyme. 1988;39(2):78–89. [PubMed] [Google Scholar]
- Estrada P., Mata I., Dominguez J. M., Castillón M. P., Acebal C. Kinetic mechanism of beta-glucosidase from Trichoderma reesei QM 9414. Biochim Biophys Acta. 1990 Mar 26;1033(3):298–304. doi: 10.1016/0304-4165(90)90137-l. [DOI] [PubMed] [Google Scholar]
- Umezurike G. M. The active site of beta-glucosidase from Botryodiplodia theobromae. Effects of pH and dioxan on enzyme-catalysed reactions. Biochem J. 1977 Dec 1;167(3):831–833. doi: 10.1042/bj1670831. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Umezurike G. M. The mechanism of action of beta-glucosidase from Botryodiplodia theobromae Pat. Biochem J. 1987 Jan 15;241(2):455–462. doi: 10.1042/bj2410455. [DOI] [PMC free article] [PubMed] [Google Scholar]