Acetaldehyde formation by mitochondria from the free-living nematode Panagrellus redivivus.

The mitochondrial fraction from the free-living nematode Panagrellus redivivus decarboxylates pyruvate to produce significant amounts of acetaldehyde. Acetaldehyde formation is stimulated by thiamin pyrophosphate, shows a sharp optimum at pH 6.8 and is greater under anaerobic than aerobic conditions. The pyruvate decarboxylase activity cofractionates with, and is probably a partial reaction of, the pyruvate dehydrogenase complex. Acetaldehyde production is modulated by NAD+, ATP and acetyl-CoA and is greatly stimulated by lipoic acid. The pyruvate decarboxylase system is extremely sensitive to thiol-group inhibitors and is inhibited by oxygen in the presence of pyruvate.