Der biologische Abbau der 1,2-Dioxybuttersäuren

Abstract

Five millimols/kg. of body wt. of the neutralized acids were injected into the ear vein of small dogs, blood specimens were obtained and urine was collected for 24 hrs. Injected d-threodihydroxybutyric acid was oxidized since it disappeared from the blood and only 25% was recovered in the urine; also glucose and 1(+)-lactic acid increased in the blood. 1-Threodihydroxybutyric acid disappeared slowly from the blood, 77% was recovered in the urine, and blood glucose and lactic acid were unchanged. Injected dl-erythrodihydroxybutyric acid was decomposed as rapidly as l( + )-lactic acid. Injection of dl-erythro- and d-threodihydroxybutyric acid into phlorizinized diabetic dogs showed these acids to be glucose forming and.anti-ketogenic. Pure dl-erythrodihydroxybutyric acid was an excellent hydrogen donator (Thunberg and Warburg techniques), considerably better than dl-threodihydroxybutyric acid. The pH optimum for the erythrodihydroxybutyric acid dehydrogenase was 7.5, and the Michaelis constant was 0.02 M.