Electronic Effects on the Trypsin-catalysed Hydrolysis of Arginine Substrates

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Okiei, W.O.
Somorin, O.
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Journal of Science Research and Development
The trypsin-catalysed hydrolysis of fifteen chromogenic arginine substrates namely Nth-benzylocarbonyl-L-arginine-X-substituted anilide (where X= F, Cl, Br, I, H, NO2, CF3, CH3 or OCH3, at the meta 9r para position of the anilide moiety) was studied. The substituted aniline released after enzymatic hydrolysis of the substrate was quantitatively determined by the Bratton Marshall reaction. The catalytic rate constant and the binding constant for the enzymatic hydrolysis of each substrate were determined and found to differ significantly for the various anilides. It was observed that the more the electron-donating power of the group attached to the aniline moiety of the substrate, the higher the rate if hydrolysis by trypsin. Binding of the substrate is enhanced by the electron-withdrawing substituents. The Hammett plots of the catalytic rate constant, kcat, against the σ values of substituents at 37oC, gave a fair correlation with a ρ value of -0.85. The negative ρ value indicates that electron-donating substituents on the substrates enhance the rate of hydrolysis by trypsin
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Research Subject Categories::NATURAL SCIENCES::Chemistry , Arginine , enzymatic hydrolysis , chromogenic arginine , catalytic rate constant
Okiei, W. O., & Somorin, O. (2003). Electronic Effects on the Trypsin-catalysed Hydrolysis of Arginine Substrates. Journal of Science Research and Development, Vol.8(1), 1-10.