Studies on the Biochemistry of Disinfection by Monochloramine

Citation

Boyle, William Charles (1963) Studies on the Biochemistry of Disinfection by Monochloramine. Dissertation (Ph.D.), California Institute of Technology. https://resolver.caltech.edu/CaltechTHESIS:09192011-095341446

Abstract

The chemical characteristics of monochloramine and some of its effects on Escherichia coli were studied. Under certain conditions monochloramine-treated cells recovered in the presence of excess thiols or thiosulfate. Such recovery could not be attributed to activation of sulfur containing respiratory enzymes.

A mechanism of the reaction of monochloramine with amino acids was proposed. The sulfur containing groups were most reactive, followed by the guanidino, amino, imidazoyl and indole groups, and purines and pyrimidines. Sugars (lactose, glucose, ribose) were very unreactive. It was estimated that most of the cellular reactivity with monochloramine was instantaneous, resulting from reactions with sulfur groups.

Monochloramination of resting cells inhibited: (a) the oxidation of glucose, succinate, acetate and pyruvate; (b) the fermentation of glucose, fructose-l,6-diphosphate and pyruvate; and (c) the dehydrogenation of succinate, lactate, formate and fructose-1, 6-diphosphate. Fermentation was the most sensitive, and formate and lactate dehydrogenases the least sensitive. In general, inhibition of enzyme activity by monochlorarmine was less than loss in viability. The induction of β-D-galactosidase was considerably less sensitive than any systems tested to monochloramine.

Results of these investigations implicate no one biochemical site of monochloramine action. Attempts to isolate monochloramine induced auxotrophic and monochloramine-resistant mutants were unsuccessful.

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