Barbosa M F, Lee H
Department of Environmental Biology, University of Guelph, Ontario, Canada.
Appl Environ Microbiol. 1991 Jul;57(7):1880-5. doi: 10.1128/aem.57.7.1880-1885.1991.
Following cell fractionation in sucrose density gradients, plasma membrane Mg(2+)-ATPase from Pachysolen tannophilus was studied. The ATPase displayed an apparent Km for ATP of 1.42 mM and was inhibited by high concentrations of Mg2+. The inhibitory effects of ethanol, 1-propanol, 1-butanol, and benzyl alcohol on Mg(2+)-ATPase were evaluated, and the concentration of each alcohol that inhibited ATPase activity by 50% (IC50) was determined. The IC50 decreased as the chain length of the alcohol increased. Moreover, the IC50 for ATPase activity was similar to the IC50 for growth rate, suggesting an association between impaired growth and ATPase inhibition. Almost complete inhibition of ATPase activity occurred at temperatures approaching 60 degrees C, and the optimal temperature was around 44 degrees C for ATPase from both control and ethanol-treated cells. Inclusion of 50 mM MgCl2 or CaCl2 in the medium did not rescue cells from the deleterious effects of ethanol.
在蔗糖密度梯度中进行细胞分级分离后，对嗜鞣管囊酵母的质膜Mg(2+)-ATP酶进行了研究。该ATP酶对ATP的表观Km为1.42 mM，并受到高浓度Mg2+的抑制。评估了乙醇、1-丙醇、1-丁醇和苯甲醇对Mg(2+)-ATP酶的抑制作用，并确定了每种醇抑制ATP酶活性50%（IC50）的浓度。随着醇链长度的增加，IC50降低。此外，ATP酶活性的IC50与生长速率的IC50相似，表明生长受损与ATP酶抑制之间存在关联。在接近60℃的温度下，ATP酶活性几乎完全被抑制，对照细胞和乙醇处理细胞的ATP酶的最佳温度约为44℃。在培养基中加入50 mM MgCl2或CaCl2并不能使细胞免受乙醇的有害影响。
