Carbon dioxide fixation by cell-free extracts of group D streptococci

Abstract

Cell-free extracts of group D streptococci incorporated 14CO2 into aspartate. Pyruvate was the acceptor of CO2 for Streptococcus faecium; phosphoenolpyruvate was the CO2 acceptor for S. bovis; and both substrates were CO2 acceptors for S. faecalis. The enzymes, by which the CO2 fixation was effected, appear to be pyruvate carboxylase for S. faecium, phosphoenolpyruvate (PEP) carboxykinase and PEP carboxylase for S. bovis, and pyruvate carboxylase and PEP carboxykinase for S. faecalis.