The activation of lactic dehydrogenase and its relation to the rôle of vitamin B1

Abstract

A soluble cell-free lactic dehydrogenase from heart muscle was prepared in a purer form than hitherto; 2 factors are necessary for its activation. Methods for the preparation from yeast of the first factor (apparently identical with Szent-Gyorgyi''s coenzyme) and for a mixture of the 2 factors were worked out. Neither factor appeared to be identical with cozymase. Using the system enzyme+lactate + mixture of 2 coenzymes, addition of methylene blue was found to be necessary before the system could take up oxygen. There was evidence that the 2nd coenzyme may be concerned with the removal of pyruvic acid. The coenzymes were obtained free from vit. B1, but the 2nd factor seemed to show some temporary curative effect on the bradycardia produced in vit. B1-deficient rats.