Synergistic Activation by Monoclonal Antibodies of β-Galactosidase from Genetically Defective E. Coli
The β-galactosidase (EC 184.108.40.206) proteins synthesised by certain mutant forms of Escherichia coli have little or no ability to catalyze the hydrolyses of galactosides unless activated by treatment with antibodies directed against the enzyme from a strain of E. coli not mutated at the same genetic locus1,2. This activation is usually regarded as being mediated by conformational changes in the β-galactosidase protein1,3 sometimes with the additional assumption that the enzyme protein is constrained to a single active conformation by the antibodies. The results presented here imply that the activation is not a simple correction of a conformational defect, that many distinct active states of the enzyme exist, and that the kinetic mechanism followed during catalysis differs depending on the particular active state conferred by the antibodies.
KeywordsSynergistic Activation Ascitic Fluid Mutant Form Immunoglobulin Isotype Conformational Defect
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- 2.W. Messer and F. Melchers, The activation of mutant β-galactosidase by specific antibodies, in:“The Lactose Operon”, J.R. Beckwith and D. Zipser, eds., pp 305–315, Cold Spring Harbor Press. (1970).Google Scholar
- 11.J. Hewitt, R.J.S. Duncan, and P.D. Weston, Hybridoma antibody mediated activation of β-galactosidases from genetically defective E. coli, in:“Protides of the Biological Fluids,” M. Peeters, ed., vol 29 in the press. (1981).Google Scholar
- 12.P.D. Weston and R.J.S. Duncan. Unpublished observations.Google Scholar