Biosynthesis of dicarboxylic acids by carbon dioxide fixation. II. Further study of the properties of the "malic" enzyme of pigeon liver.

This enzyme is provisionally referred to as “malic” enzyme. The present paper deals with further observations on the kinetics and other properties of the purified enzyme.’ The enzyme is totally inactive in the absence of Mn++. Mg++ can replace Mn++ but is less effective. Further evidence has been obtained indicating that free oxalacetate is not an intermediate in Reaction 1 and that both Reactions 1 and 2 are catalyzed by one and the same enzyme. Additional evidence has also been obtained showing that the dismutation between malate and pyruvate (2,3), represented by Reaction 3, is catalyzed