Yeast aldehyde dehydrogenase

Abstract

Summaryo1.A soluble enzyme has been isolated from baker's yeast which catalyzes the reduction of pyridine nucleotides by several aldehydes. With acetaldehyde, the most rapidly utilized substrate, the oxidative product is acetic acid. A reverse reaction was not demonstrated.2.Potassium ions and cysteine are essential for the enzyme's activity. Rubidium or NH4+ can be substituted for K+, and glutathione for cysteine. Lithium, Na+, and Cs+ inhibit the reaction.3.A procedure is described for concentrating the enzyme about 300-fold from crude yeast juice. This procedure is largely dependent upon heat precipitation of inactive proteins in the presence of nucleic acid and precipitation of the enzyme as a nucleic acid complex in acid solution, followed by precipitation from saturated NaCl. A soluble enzyme has been isolated from baker's yeast which catalyzes the reduction of pyridine nucleotides by several aldehydes. With acetaldehyde, the most rapidly utilized substrate, the oxidative product is acetic acid. A reverse reaction was not demonstrated. Potassium ions and cysteine are essential for the enzyme's activity. Rubidium or NH4+ can be substituted for K+, and glutathione for cysteine. Lithium, Na+, and Cs+ inhibit the reaction. A procedure is described for concentrating the enzyme about 300-fold from crude yeast juice. This procedure is largely dependent upon heat precipitation of inactive proteins in the presence of nucleic acid and precipitation of the enzyme as a nucleic acid complex in acid solution, followed by precipitation from saturated NaCl.