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Study of Na+ transporting atpase from marine unicellular alga Tetraselmis (Platymonas) viridis during adaptation to different salinityстатья
- Авторы: Strizh I., PopovaL, Andreev I., Balnokin Yu
- Журнал: European Journal of Biochemistry
- Том: 268
- Номер: S1
- Год издания: 2001
- Первая страница: 237
- Последняя страница: 238
- Аннотация: Tetraselmis (Platymonas) viridis, a marine unicellular green microalga possesses an electrogenic, vanadate-sensitive, plasma membrane (PM) Na+ -ATPase. This alga successfully tolerates seawater salinity (0.5 m NaCl). Furthermore, it is able to grow in the wide range of salt concentrations at almost the same rate. The regulation of sodium efflux across the PM is thought to be achieved by the sodium pump. In this study, the changes in kinetic parameters of PM Na+ -ATPasein response to NaCl treatment was characterized. PM vesicles were isolated from the alga cultures growing for at least 7 days (long-term adaptation) at 10 mm, 50 mm, 500 mm, 900 mm and 1.2 m NaCl in an artificial sea water. As it has been shown earlier, operation of T. viridis Na ± ATPase is accompanied by countertransport of H+. In present study formation of the interior alkaline pH gradient across the vesicle membranes in the course of sodium pumping was monitored with the pH indicator pyranine loaded into the vesicles. Apparent Km value of 0.08 mm for Na+ was found for this model system. This value did not change during alga adaptation to different salt concentrations. SDS/PAGE of PM proteins did not reveal the induction of 100 kDa polypeptide corresponding to the Na+ -ATPase in salt-adapted cells. This study suggests that the sodium pump of Tetraselmis should be the constitutive enzyme with high affinity to Na+.
- Добавил в систему: Стриж Ирина Георгиевна