Kaloyianni M, Tsikriktsi O, Tsianopoulou P
Zoology Department, Science School, Aristotle University of Thessaloniki, Greece.
Gen Physiol Biophys. 1998 Jun;17(2):143-56.
The present report confirms the presence of Na(+)-K(+)-Mg2+ ATPase in the erythrocyte membranes of the frog Rana balcanica (previously Rana ridibunda) (Schneider et al. 1993; Sofianidou et al. 1994). The Na(+)-K(+)-Mg2+ ATPase activity was 60% reduced by the presence of ouabain. The pH optimum was 8.0, the optimum Mg2+:ATP concentration ratio was 2.2:1. The existence of an ATPase with a high K(m) for ATP (1.48 mmol/l) was postulated. At pH 7.4 and 8.0, the adenine nucleotide pattern of glucose-depleted erythrocytes showed a characteristic reduction in ATP contents. Adenine nucleotide concentrations were higher at pH 7.4 than at pH 8.0. Ouabain inhibited ATP breakdown at both pH values studied. The strongest inhibition was observed at pH 7.4. The decline of the total contents of adenine nucleotides appears to be determined by the rate of AMP breakdown.
本报告证实了在巴尔干林蛙（以前称为食用蛙）的红细胞膜中存在Na(+)-K(+)-Mg2+ ATP酶（施耐德等人，1993年；索菲阿尼杜等人，1994年）。哇巴因的存在使Na(+)-K(+)-Mg2+ ATP酶活性降低了60%。最适pH值为8.0，最适Mg2+:ATP浓度比为2.2:1。推测存在一种对ATP具有高K(m)值（1.48 mmol/l）的ATP酶。在pH 7.4和8.0时，葡萄糖耗尽的红细胞的腺嘌呤核苷酸模式显示ATP含量有特征性降低。pH 7.4时的腺嘌呤核苷酸浓度高于pH 8.0时。在研究的两个pH值下，哇巴因均抑制ATP的分解。在pH 7.4时观察到最强的抑制作用。腺嘌呤核苷酸总含量的下降似乎由AMP分解速率决定。
