The effects of guanidinium chloride, urea and sodium dodecyl sulfate on the endoproteinase Glu-C- catalyzed hydrolysis of N-t-BOC-L-glutamic acid-gas-phenyl ester

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Delk, Roger D.
Johnson, Eric R.
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Thesis (M.S.)
Department of Chemistry
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Endoproteinase Glu-C (EPGIu-C, EC, an enzyme isolated from the bacteria Staphylococcus aureus, has been found to cleave specifically at the carboxyl-terminal side of glutamyl and aspartyl peptide bonds. EPGIu-C has been reported to be stable and active in the presence of common denaturants such as guanidinium chloride, urea and sodium dodecyl sulfate (Drapeau, G.R. (1977) Methods in Enzymology, 47:189-191). In order assess the denaturant stability and activity of EPGIu-C, the effect of three common protein denaturants, guanidinium chloride, urea, and sodium dodecyl sulfate (SDS) on the proteolytic activity of EPGIu-C was studied.The kinetics of the hydrolyis reaction catalyzed by EPGIu-C was determined using the chromophoric substrate N-tBOC-L-glutamic acid-a-phenyl ester (BGPE).To compare theurea is significantly greater at the higher concentrations of urea. These results suggest that a complete cleavage of proteins substrate by EPGlu-C might occur more rapidly in 8.0 M urea than in 6.0 M GuCl, since EPGlu-C will be operating at a significantly higher catalytic efficiency in the urea solution.