关键词: 胆固醇, 线粒体ATP酶, 膜相变温度

Abstract: Exogenous cholesterol was added in two ways:one was that exogenous cholesterol was absorbed by root system during water culture of rice$ the other was adding it directly to the prepared mitochondria of control rice root apex, and incubating it at 8℃ for 30 minutes. The ATPase activity was then determined. The result indicated that exogenous cholesterol in the given range of concentrations increased the ATPase activity of mitochondria in rice root apex in the either Way. It was also observed that exogenous cholesterol markedly decreased the break point temperatures of ATPase AEa of mitochondria, into which the cholesterol was absorbed by root system, from 27.7℃ and 15.5℃ in the control to 24.5℃ and 12.7℃, respectively; and that of the mitochondria, with which the cholesterol was directly incubated, decreased to 18.8℃ and 9.6℃, respectively. This result indicates that the proper amount of exogenous cholesterol not only has an apparent accelerating effect on the ATPase activity in rice apex mitochondria, but also a regulating effect on the decrease of phase transition temperature of mitochondria membrane.

Key words: Cholesterol, Mitochondria ATPase, Membrane phase transition temperature