Sur la détermination des sites actifs de certaines enzymes au moyen d'un nouveau réactif spécifique: IV. Fixation de divers substrates sur le chlorhydrate de polyvinylamine et sur la polyacrylylhistamine le sel de roussin

Abstract

In earlier communications was shown, by measurements of the inhibition kinetics with the Roussin's salt ([Fe 4S 3(NO) 7K), that certain substrates fix themselves on the basic groups of the active sites of a series of enzymes. Wishing to confirm these results by a direct measurement of fixation of the substrates on the basic groups of macomolecules of a given chemical structure, the polymers polyvinylamine hydrochloride and polyacrylylhistamine were chosen, where the functional groups are NH 3 + and imidazole respectively. The method employed was equilibrium dialysis. The result is that the polyacrylylhistamine does not fix any of the substrates employed in pH range 6–8. On the contrary, polyvinylamine fixes all except glucose and ethanol. However, for most of the substrates (which are electrolytes and in which the active element is an anion), this fixing is purely electrostatic and consequently unspecific. On the other hand, the polyvinylamine fixes the α-ketoacids and linoleic acid in preference to the other anions. In all the 18 cases studied, the results obtained by the direct method of fixation agree with those deduced from the inhibition by Roussin's salt. The use of high polymers may be useful in the studies of the preferential fixation of substrates on diverse functional groups.