Effect of glucose, its analogs and some amino acids on pre‐steady state kinetics of ATP hydrolysis by PM‐ATPase ofpathogenic yeast(candida albicans)

Abstract

Fast kinetics of transient pH changes and difference spectrum formation have been investigated following mixing of ADP/ATP with partially purified plasma membrane PM‐ATPase of the pathogenic yeast Candida albicans in the presence of five nutrients: glucose, glutamic acid, proline, lysine, and arginine and two analogs of glucose: 2‐deoxy D‐glucose and xylose. Average hT‐absorption to release ratio, indicative of population of ATPase undergoing complete hydrolytic cycle, was found to be 0.27 for control. This ratio varied between 0.25 (proline) to 0.36 (arginine) for all other compounds tested, except for glucose. In the presence of glucose, H+‐absorption to release ratio was exceptionally high (0.92). While no UV difference spectrum was observed with ADP, mixing of ATP with ATPase led to a large conformationai change. Exposure to different nutrients restricted the magnitude of the conformationai change; the analogs of glucose were found to be ineffective. This suppression was maximal in the case of glucose...