Enzymology of Vicinal Diketone Reduction in Brewer's Yeast

Ale and lager strains of yeast contain multiple enzymes capable of reducing diacetyl and pentanedione. Alcohol dehydrogenase is probably the main activity responsible in both types of organism. Although it appears that the lager strain studied possesses a more complex portfolio of diacetyl reductases than does the ale strain, it is likely that alcohol dehydrogenase has proportionately greater impact on vicinal diketone reduction in the lager strain. Two diacetyl reductases additional to alcohol dehydrogenase were located in a partial purification operation based on lager yeast, but only a single such enzyme was revealed in ale yeast.