Transport of B-Vitamins in Microorganisms. VIII. Comparative Studies on Membrane Bound ATPase(s) Obtained from Normal and Niacin Deficient Cells of S. faecalis.

Publisher Website
Google Scholar
Abstract
Cytoplasmic membranes were prepared from normal and niacin deficient cells of S. faecalis by direct lysis of the intact cells in the presence of lysozyme. The Pi releasing activities of the membrane preparations were studied using ATP and certain other phosphate containing substrates. Both kinds of preparation contained Mg2+-activated ATPase which was, at least in the preparations from normal cells, further stimulated by certain concentrations of K+ and Na+. The activation by Mg2+ was lowered in the presence of Ca2+. Comparative studies on 18 preparations from normal and 18 preparations from niacin deficient cells indicated that the specific ATPase activity of the membranes was considerably depressed in niacin deficiency. The membrane material also contained inorganic pyrophosphatase, the specific activity of which was, in preparations from normal cells, equal to that of the ATPase, whereas it was lower than the specific ATPase activity in membranes from niacin deficient cells. The membrane preparations released approximately ten times more Pi from ATP than they did in the presence of ADP; AMP was not hydrolyzed by the preparations.

This publication has 0 references indexed in Scilit: