Yeast lactic dehydrogenase and cytochrome b2

Abstract

Lactic dehydrogenase of yeast was extracted and concentrated. Increasing instability made it difficult to purify. It did not depend on soluble coenzymes or on flavin groups for activity. A new cytochrome (cytochrome b2), water soluble, was found in the concentrated enzyme prepns., and showed a strong absorption band at 5565 A. It formed an essential part of the enzyme system, either as dehydrogenase or as an intermediate carrier between lactate and methylene blue. An additional factor was necessary for its reaction with cytochrome c.