Studies on the nicotinic acid oxidase of pseudomonas fluorescens.

The past twenty years have witnessed remarkable advances in the problems associated with the assay of accessory food substances by means other than biological assays. Chemical, spectrographic and microbiological methods have been applied with varying degrees of success; and the problems involved have exerted an appreciable influence over the entire field of biochemical analysis. More strictly physiological work has made it possible to assign specific biochemical functions to certain of the substances involved. A classic instance is the role of thiamine as a constituent of co-carboxylase. Research on the possible parts played by these substances in cell metabolism has, in fact, become a major subdivision of biochemical research. [...] The action of the organism is believed to be due to the presence of an enzyme system which is highly specific for the destructive oxidation of nicotinic acid and which has been provisionally named nicotinic acid oxidase. The specificity and activity of the enzyme are such that it can be applied to the determination of nicotinic acid. The research described in the present thesis is an extension of this work. It has centered round three main issues: (a) the elucidation of the mode of action of nicotinic acid oxidase by experiments involving the use of various analogues and inhibitors, (b) the isolation of nicotinic acid oxidase from the bacterial cell and (c) the identification of intermediate and end products of the nicotinic acid oxidation.[...