[Effect of p-chloromercuribenzoate on glutamine synthetase in the food yeast Candida tropicalis].

The effect of p-CMB on the activity of glutamine synthetase in the fodder yeast Candida tropicalis was studied in the synthetase reaction in Mg-, Mn-, and Co-activated systems and in the transferase reaction. The activity of glutamine synthetase was inhibited by pCMB, the degree of inhibition depending on the presence of bivalent cations of metals. Preliminay incubation of the enzyme with p-CMB stimulated the action of the latter, whereas metals increased the stability of the enzyme to pCMB. If the enzyme preparation was purified, it became more susceptible to the action of p-CMB. The transferase activity was also inhibited by p-CMB but to a less extent that the synthetase reaction.