The Inhibition of Sulfhydryl Enzymes as the Basis of the Bactericidal Action of Chlorine

Abstract

Current hypotheses of the mode of bactericidal action of chlorine suppose a direct combination of some chemical 'species of the chlorine with the bacterial protoplasm producing a toxic organic complex (Porter, 1946). Although this view is a great advance over earlier concepts, it still lacks precision in terms of our present knowledge of the intermediary metabolism of cells. The marked efficiency of chlorine, exerting a bactericidal action in concentrations of 0.2 to 2.0 ppm in water, will at once classify it as a biologically active "trace substance." It may consequently be assumed to exert its effect upon the enzyme systems of the cell (Green, 1941). By investigation of the effect of chlorine on bacteria and on various enzymes, its bactericidal effect has been shown to depend upon the inhibition of certain essential enzyme systems, and the mechanism of this inhibition involves the powerful oxidative action of chlorine on the-SH groups of these enzymes. METHODS Active chlorine was estimated by the acid-iodine thiosulfate titration procedure (Calvert, 1943). Chlorine solutions, when not otherwise specified, were obtained by neutralizing and filtering a fresh solution of calcium hypochlorite. 'This investigation was conducted under contract with the Committee on Medical Research of the Office of Scientific Research and Development and at the request of the Office of the Quartermaster General.

Resistance to chlorine of freshwater bacterial strains

“…On the other hand, more information and theoretical considerations about the mechanisms of microbial inactivation by chlorine (Green and Stumpf 1946 ;Knox et al 1948 ;Hugo Correspondence to : 3'. Morato Schalenkamp 1986) and several models of inactivation kinetics, based on Chick's Law (first order decay kinetics) and others (Sykes 1958 ;Prokop and Humphrey 1970), have been available.…”

Chlorine resistance patterns of bacteria from two drinking water distribution systems

“…In aqueous environments, uncombined chlorine, in the form of unionized hypochlorous acid (HOCl), is an extremely potent bactericidal and virucidal agent, even at concentrations of less than 0.1 mg liter-' (22). Chlorine is known to exert disruptive effects on a variety of subcellular components and metabolic processes (13), including: (i) in vitro formation of chlorinated derivatives of purine and pyrimidine nucleotide bases (10), (ii) oxidative decarboxylation of amino acids (27) and other naturally occurring carboxylic acids (19), (iii) inhibition of enzymes involved in intermediary metabolism (8,18), (iv) inhibition of protein biosynthesis (5), (v) introduction of singleand double-stranded lesions into the bacterial chromosome (33), (vi) production of bacterial mutations (32), (vii) inhibition of membranemediated active transport processes and respiratory activity (8), and (viii) uncoupling of oxidative phosphorylation accompanied by leakage of macromolecules from the cell (35,36). Chlorine has also been shown to cause physiological injury of coliform microorganisms such as Esch-erichia coli, resulting in underestimation of these indicator organisms in chlorinated waters (7,8).…”

Adenovirus inactivation by in situ photocatalytically and photoelectrocatalytically generated halogen viricides

“…Although the oxidation power of these species are not high, they should be sufficient to cause damage to the capsid of nonenveloped viruses (such as adenovirus), whose capsid is composed of protein polypeptides. Also, HOX prefers to react with amino acids with an amino group side chains [38], and is particular effective to inactivate proteins containing sulfhydryl groups [38]. Therefore, HOX could play an important role in the damage of the protein capsid of RDRADS.…”