It is widely accepted that urea and guanidine act as protein denaturants by breaking intramolecular hydrogen bonds (1). Loss of catalytic activity in the presence of urea is thought to occur by elimination of bonds contributing to the tertiary structure of enzyme molecules. Subsequent restoration of structural and catalytic properties by removal of the denaturant, “reversible denaturation,” is ...

It is widely accepted that urea and guanidine act as protein denaturants by breaking intramolecular hydrogen bonds (1). Loss of catalytic activity in the presence of urea is thought to occur by elimination of bonds contributing to the tertiary structure of enzyme molecules. Subsequent restoration of structural and catalytic properties by removal of the denaturant, “reversible denaturation,” is ...

A non-competitive inhibition by glucose-6-P1 of brain (1, 2) and other animal tissue (1) hexokinases has been described, as well as a similar inhibition of brain hexokinase by L-sorbose-1-P (3). The present paper is concerned with the specificity for inhibition of brain hexokinase by glucose6-P and related compounds. Ry means of a comparison of the structures of twenty-five compounds, six of xv...

The concentration of an inhibitor that decreases the rate of an enzyme-catalysed reaction by 50%, symbolized i(0.5), is often used in pharmacological studies to characterize inhibitors. It can be estimated from the common inhibition plots used in biochemistry by means of the fact that the extrapolated inhibitor concentration at which the rate becomes infinite is equal to -i(0.5). This method is...

The interactive inhibitory effects of pH and chloride on the catalysis of laccase from Trametes versicolor were investigated by studying the alteration of inhibition characteristics of sodium chloride at different pHs for the oxidation of 2,2'-azino-bis (3-ethylbenzthiazoline-6-sulfonic acid). At pH 3.0, the addition of sodium chloride (50 mM) brought about a 40-fold increase in Km(app) and a 4...