The synthesis of cozymase from nicotinic acid and its derivatives by Lactobacillus arabinosus 17–5

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Abstract
Glycolyzing washed suspensions of cozymase-deficient cells of L. arabinosus 17-5 synthesized cozymase from nicotinic acid, nicotinamide riboside and nicotinamide ribotide. The newly-formed cozymase stimulated the rate of glycolysis by the cells from 2- to 5-fold. Max. stimulation occurred in the presence of 1-5.0 x 10-6[image] nicotinic acid. As judged by their effects on glycolysis, nicotinamide, nicotinamide riboside and ribotide were more readily available for cozymase synthesis in older cells than was nicotinic acid. The rate of cozymase synthesis in any batch of cells was dependent on the added nicotinic acid concn. and was max. at and above 5 x 10-5[image] nicotinic acid. The max. rate of cozymase synthesis (18-24[mu]m-moles/mg. dry wt./hr.) occurred in cells grown for 18-24 hrs. and fell progressively as the cells were grown for longer periods. Cozymase synthesis and the uptake of nicotinic acid ceased when the cells contained from 10 to 12 jim-moles cozymase/mg. dry wt. Cozymase uptake and synthesis and the uptake of nicotinic acid and nicotinamide did not occur in the absence of glucose. No other constituent of the growth medium had marked effect on these processes. Nicotinamide was deamidated rapidly (1-2 [mu]moles/mg. dry wt./hr.). This reaction was independent of the presence of glucose and of the cozymase content of the cells.