Hartman R E
J Bacteriol. 1970 May;102(2):341-6. doi: 10.1128/jb.102.2.341-346.1970.
Extracts of cells of Streptococcus faecalis var. liquefaciens strain 31 incorporated (14)CO(2) into aspartate. Dialyzed extracts produced radioactive oxalacetate in the absence of exogenously added glutamate and pyridoxal-5'-phosphate and produced radioactive aspartate in the presence of these components. Reduced nicotinamide adenine dinucleotide or reduced nicotinamide adenine dinucleotide phosphate could not be substituted for adenosine triphosphate (ATP); phosphoenolpyruvate even in the presence of nucleoside diphosphates could not replace pyruvate plus ATP; propionate plus coenzyme A (CoA) could not replace pyruvate in supporting CO(2) fixation by cell extracts. Fixation by dialyzed cell extracts required pyruvate, ATP, MgSO(4), and was stimulated by biotin, KCl, 2-mercaptoethanol, CoA, and acetyl CoA. Inhibition of fixation occurred when avidin, NaCl, oxalacetate, or aspartate was added to dialyzed extracts. On the basis of the products formed and the effects of substrates and cofactors on the fixation reaction, it was concluded that pyruvate carboxylase is responsible for CO(2) fixation in this microorganism.
粪链球菌液化变种31菌株的细胞提取物能将（14）CO₂掺入天冬氨酸。透析后的提取物在没有外源添加谷氨酸和磷酸吡哆醛-5'-磷酸的情况下产生放射性草酰乙酸，并在有这些成分存在时产生放射性天冬氨酸。还原型烟酰胺腺嘌呤二核苷酸或还原型烟酰胺腺嘌呤二核苷酸磷酸不能替代三磷酸腺苷（ATP）；即使在核苷二磷酸存在的情况下，磷酸烯醇丙酮酸也不能替代丙酮酸加ATP；丙酸加辅酶A（CoA）不能替代丙酮酸来支持细胞提取物固定CO₂。透析后的细胞提取物固定CO₂需要丙酮酸、ATP、MgSO₄，并受到生物素、KCl、2-巯基乙醇、CoA和乙酰CoA的刺激。当向透析后的提取物中加入抗生物素蛋白、NaCl、草酰乙酸或天冬氨酸时，固定作用受到抑制。根据形成的产物以及底物和辅因子对固定反应的影响，得出结论：丙酮酸羧化酶负责该微生物中的CO₂固定。
