THE INFLUENCE OF COBAMIDES ON THE ENDOGENOUS AND EXOGENOUS RESPIRATION OF A MARINE BACTERIUM

Abstract

The oxidation of propionate, isobutyrate, valerate, isoleucine, and valine as well as the endogenous respiration of a B12-dencient marine bacterium was stimulated by the addition of vitamin B12to washed cell suspensions. The B12analog, 2-methyladenylcobamide cyanide, also stimulated endogenous respiration, but cobinamide was inactive. During autorespiration ammonia was continuously evolved by the cells indicating the presence of a nitrogenous endogenous substrate. When vitamin B12was supplied to the cells, the ammonia evolved was decreased, while the rate of oxygen uptake was increased. The possible involvement of cobamide coenzymes is discussed in relation to these findings.