Effect of metal ions on pea alcohol dehydrogenase

Abstract

The effect of Cu2+, Ag+, Zn2+, Cd2+ and Co2+ on alcohol dehydrogenase (ADH) isolated from germinating pea seeds was examined. The enzyme is inhibited approximately to the same degree if incubated 5 to 30 min with Ag+, Cu2+, and Cd2+; the same degree of inhibition can be brought about by zinc ions only if concentration by one order higher (10-4M) is used. Co2+-ions do not inhibit pea alcohol dehydrogenase even at 10-3M concentration. NAD and Zn2+ decrease the inhibitory effect of Cd2+ yet not the effect of Cu2+ or Ag+. The differences in the mechanism of action of individual heavy metal ions on plant ADH are discussed.