The synthesis of coenzyme A by Lactobacillus arabinosus 17–5

Abstract

I954 cation of the enzyme with an over-all yield of 20 % was effected.3. A purified preparation of the enzyme attacked all three phosphoproteins studied, but had no appreciable action on glycerophosphate or casein phosphopeptone. The enzyme is hence a true phosphoprotein phosphatase, distinct from the acid phosphomonoesterase.4. Optimum enzyme activity was found at pH 6-0 and at a substrate concentration corresponding to about 10,umoles/ml. of casein phosphorus with 0 001 M thioglycollic acid as activator.5. From the activation and inhibition studies it is deduced that sulphydryl and amino groups are essential for the activity of the enzyme. However the enzyme requires no dialysable coenzyme for its activity.The authors wish to thank the University of Madras for the award of a research studentship to one of us (T. A.S.) and for kind permission to publish the results which form part of a thesis approved for the degree of Master of Science.

The Absorption of Bound Forms of B‐group Vitamins by Rat Intestine

“…The presence of pantetheine would result in high values in this assay [Pierpoint, 1954] but no account was taken of this in the present work.…”

“…Estimation of Coenzyme A (CoA).--The acetylation of 4-amino azobenzene as described by Handschumacker, Mueller and Strong [1951] was found to be most satisfactory for the assay of CoA. The presence of pantetheine would result in high values in this assay [Pierpoint, 1954] but no account was taken of this in the present work.…”

“…Lactobacillus arabinosus as used in the nicotinic acid assay responds equally to nicotinamide, nicotinamide riboside but not to the phosphorylated forms [Mcllwain, Stanley and Hughes, 1949]. In the pantothenic acid assay the organism responds to pantetheine but not to the phosphorylated forms of the vitamin [Pierpoint and Hughes, 1954].…”

Metabolism of β-mercaptoethylamine. 1. In mice

“…It is not known whether part of the 'bound' cysteamine (pantetheine, coenzyme A) may not also be involved, but this is not important if 'free' cysteamine cannot be bound and thus introduce radioactivity into such molecules as coenzyme A. It seems that such is actually the case, since the S of cysteamine is not utilized for cystine biosynthesis, and cysteamine does not seem to be directly used for pantetheine and coenzyme A biosyntheses (Brown & Snell, 1953;Pierpoint & Hughes, 1954).…”

Vertebrate Radiobiology (Lethal Actions and Associated Effects)

“…� Although cysteamine is a component of CoA, recent work indicates that cystea mine cannot replace cysteine or cystine in the biosynthesis of this substance (170). 5 There is an unfortunate ambiguity in this paper because of a curious omission of any mention of early deaths in the treated groups of rabbits prior to initiation of treatment.…”