Lactate dehydrogenase-6. A biochemical sign of serious hepatic circulatory disturbance.

I confirmed the existence of an additional isozyme band of lactate dehydrogenase (LD) (EC 1.1.1.27) cathodic to LD-5 utilizing agarose gel isozyme electrophoresis in seven patients. Three of the patients died of circulatory failure within three weeks after the isozyme was identified. Four patients survived after successful therapy for heart failure. The under-lying clinical condition was arteriosclerotic cardiovascular disease causing congestive heart failure with passive congestion of the major viscera. I performed biochemical analysis on the isozyme and found that it was extremely heat stable, was not immunoglobulin bound, and contained only M, not H, subunits. It may represent a posttranslationally modified LD-5 or alcohol dehydrogenase.