Characterization of the plasma membrane ATPase of Candida tropicalis.
1) Plasma membrane vesicles from Candida tropicalis were isolated from protoplasts by differential centrifugation and purified in a continuous sucrose gradient. 2) The plasma membrane bound ATPase was characterized. It is highly specific for ATP and requires Mg2+. It is stimulated by K+, Na+ and NH4+. Lineweaver-Burk plots for ATPase activity are linear with a Vmax of 4.2 mumoles of ATP hydrolyzed min-1.mg-1 protein and a Km for ATP of 0.76 mM. The ATPase activity is inhibited competitively by ADP with a Ki of 1.7 mM and non competitively by vanadate with a Ki of 3 microM. The activity is unaffected by oligomycin or azide but is sensitive to DCCD.
D000244:Adenosine Diphosphate / Q000494:pharmacology; D000251:Adenosine Triphosphatases / Q000378:metabolism*; D000255:Adenosine Triphosphate / Q000378:metabolism; D000641:Ammonia / Q000494:pharmacology; D002175:Candida / Q000201:enzymology*; D002462:Cell Membrane / Q000201:enzymology; D002499:Centrifugation, Density Gradient; D007700:Kinetics; D008274:Magnesium / Q000378:metabolism; D011188:Potassium / Q000494:pharmacology; D012964:Sodium / Q000494:pharmacology
D000244:Adenosine Diphosphate; D000641:Ammonia; D000255:Adenosine Triphosphate; D012964:Sodium; D000251:Adenosine Triphosphatases; D008274:Magnesium; D011188:Potassium