This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Drapeau, G. R. Articles by MacLeod, R. A. Search for Related Content PubMed PubMed Citation Articles by Drapeau, G. R. Articles by MacLeod, R. A.

NUTRITION AND METABOLISM OF MARINE BACTERIA XII.

Ion Activation of Adenosine Triphosphatase in Membranes of Marine Bacterial Cells¹

^a Department of Bacteriology, Macdonald College of McGill University, Quebec, Canada

ABSTRACT

DRAPEAU, GABRIEL R., (Macdonald College of McGill University, Quebec, Canada) AND ROBERT A. MACLEOD. Nutrition and metabolism of marine bacteria. XII. Ion activation of adenosine triphosphatase in membranes of marine bacterial cells. J. Bacteriol. 85:1413–1419. 1963.—Isolated membranes of two species of marine bacteria, a Pseudomonas and a Cytophaga, have been shown to possess adenosine triphosphatase activity. The optimal pH for enzyme action of both organisms was 8.8. The enzyme system was found to be capable of splitting inorganic o-phosphate from adenosine triphosphate (ATP), adenosine diphosphate, adenosine monophosphate, and inosine triphosphate but not from inorganic pyrophosphate. Mg⁺⁺ was required for enzyme activity; with the Pseudomonas species, the optimal Mg⁺⁺ to ATP ratio was 1:1. Ca⁺⁺ could not replace Mg⁺⁺. In the presence of the optimal concentration of Mg⁺⁺, the enzyme system was further stimulated, nonspecifically, by a number of different salts. Maximal activation was achieved at an ionic strength of 0.3 to 0.4. No evidence of an adenosine triphosphatase specifically activated by a combination of Na⁺ and K⁺ was obtained with either organism. No effect of ouabain on either the membrane adenosine triphosphatase activity or Na⁺ transport by whole cells could be detected. The results suggest that the mechanism of ion regulation in marine bacterial cells is different from that in animal cells.

¹ From a thesis submitted by Gabriel R. Drapeau in partial fulfilment of the requirements for the degree of Master of Science at McGill University. Presented in part at the Annual Meeting of the American Society for Microbiology, Kansas City, Mo., 6–10 May 1962. Issued as Macdonald College Journal Series no. 497.