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Inhibition of serine proteases by oxygen, sulfur and selenium dialkyl phosphoryl derivatives: Biochemical and sup 31 P NMR studies

Thesis/Dissertation ·
OSTI ID:7255455

{sup 31}P NMR spectroscopy was employed to investigate the interaction of chymotrypsin with various organophosphorus inhibitors. The {sup 31}P NMR spectrum of diethyl selenophosphoryl chymotrypsin revealed two resonances at approximately 71 ppm and a single resonance at 48 ppm attributed to the covalent and non-covalent enzyme-inhibitor complexes, respectively. The goal of this investigation was to elucidate the basis of the two peaks at {approx}71 ppm in the {sup 31}P NMR spectrum of diethyl selenophosphosphoryl-{alpha}-chymotrypsin. The possibility that the selenium atom in the structure of the organophosphorus inhibitor might have been responsible for the two peaks was addressed by extending the {sup 31}P NMR studies to diethyl thiophosphoryl- and diethyl phosphoryl-{alpha}-chymotrypsin. The fact that the latter modified enzyme derivatives also yielded {sup 31}P NMR spectra that exhibited two resonances assigned to covalent species discounted this possibility. The effect of the alkyl group of the inhibitor on the {sup 31}P NMR spectrum of the enzyme-inhibitor complex was further investigated by examining diisopropyl phosphoryl-{alpha}-chymotrypsin by {sup 31}P NMR spectroscopy.

Research Organization:
South Carolina Univ., Columbia, SC (USA)
OSTI ID:
7255455
Country of Publication:
United States
Language:
English