The synthesis of coenzyme A by Lactobacillus arabinosus 17–5

Abstract

Glycolysing, washed suspensions of Lactobacillus arabinosus 17-5 grown on a medium deficient in pantothenate can synthesize 50-100 Lipmann units of coenzyme A/g. dry wt. from pantothenate. The addition of cystine increases the amts. of coenzyme A which can be synthesized to 600-800 Lipmann units/g. dry wt. The amts. of coenzyme A synthesized are related to the initial coenzyme A content of the cells; the most deficient cells synthesize most coenzyme A. Glucose and Mg ions are essential for the synthesis. Panthetheine can replace pantothenate and cystine. Cystine is presumably required for the formation of the beta-mercaptoethylamine residue of panthetheine. It can be replaced by cysteine and partially by glutathione, but not by beta-mercapto-ethylamine, taurine, cysteic acid, homocystine, methionine, S-methylcystine, thioglycollic acid, thioacetamide, and ethanethiol. The ability of the cells to synthesize coenzyme A is smallest in cells harvested at the beginning of the log phase of growth, increases continuously during the log phase, and remains constant for at least 42 hrs. after the cells have ceased to grow. Pantothenate is removed by the cells in the absence of cystine, and reappears on treatment with alkaline phosphatase. This suggests that pantothenate is phosphorylated in the absence of cystine.