Studies on plant formic dehydrogenase

Abstract

Plant formic acid dehydrogenase was prepared from bean seeds and purified by fractional absorption on Ca phosphate. Coenzyme I is necessary but coenzyme II was ineffective. Fe+++ and Cu ++ were strongly inhibitory; Fe++, Mg++ and Mn++ were ineffective. Cyanide and azide were effective inhibitors, CO gave the same slight inhibition in light and dark, while diethylthiocarbonate and BAL were inactive. No reduction of CO2 to formate by the enzyme occurred, even in the presence of hexosedi-phosphate and ATP. The coenzyme-linked reaction between formate oxidation and reductive deamination of alpha-keto glutarate proceeded rapidly when glutarate and ammonia were added with the formate to the bean extract.