酵母中钠离子含量与标记钠离子流出之间的关系。

The relation between sodium ion content and efflux of labelled sodium ions from yeast.

作者信息

Dee E, Conway E J

出版信息

Biochem J. 1968 Mar;107(2):265-71. doi: 10.1042/bj1070265.

DOI:10.1042/bj1070265

PMID:5641880

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC1198652/

Abstract

The activity of the Na(+) pump in an Na(+)-rich yeast was compared with that in an Na(+)-rich frog sartorius muscle, and found to be very similar to it over the first hour if both were immersed in fluid containing 104mm-Na(+) plus 10mm-K(+). 2. The efflux of labelled Na(+) from an Na(+)-rich yeast into an Na(+)-free medium was investigated. In this Na(+)-free medium, Li(+) or choline replaced the Na(+), and the efflux-content curves obtained with either of these ions were very similar. The curves were sigmoid, reaching or approaching a saturation at the higher internal Na(+) concentrations. 3. The curves obtained with yeast resembled those similarly obtained with frog sartorius muscle by Keynes & Swan (1959), Mullins & Frumento (1963), Harris (1965) and Keynes (1965). The slope of the plot of the logarithm of the Na(+) efflux against the logarithm of the Na(+) concentration in the cells reached its highest value at an internal Na(+) concentration of 15m-equiv./kg. (27m-equiv./l. of cell water). 4. The effect of external K(+) concentration on the efflux-content relationship was examined. An increased K(+) concentration was found to increase the Na(+) efflux by raising the saturation value, which is similar to observations made by Harris (1965) with frog muscle. 5. The effect of increasing the external carbon dioxide concentration was investigated. No effect on the slope of the plot of the logarithm of the Na(+) efflux against the logarithm of the Na(+) content was noticed even when the yeast suspension was equilibrated with 100% carbon dioxide. There was, however, a decrease in the amount of Na(+) efflux on equilibrating the solution with carbon dioxide.

摘要

将富含Na⁺的酵母中的Na⁺泵活性与富含Na⁺的青蛙缝匠肌中的Na⁺泵活性进行了比较，发现如果将两者都浸入含有104mmol/L Na⁺加10mmol/L K⁺的溶液中，在最初的一小时内它们非常相似。2. 研究了标记的Na⁺从富含Na⁺的酵母向无Na⁺培养基中的流出情况。在这种无Na⁺培养基中，Li⁺或胆碱替代了Na⁺，用这两种离子获得的流出-含量曲线非常相似。曲线呈S形，在较高的内部Na⁺浓度下达到或接近饱和。3. 用酵母获得的曲线类似于凯恩斯和斯旺（1959年）、穆林斯和弗鲁门托（1963年）、哈里斯（1965年）以及凯恩斯（1965年）用青蛙缝匠肌类似获得的曲线。Na⁺流出对数与细胞内Na⁺浓度对数的关系图的斜率在内部Na⁺浓度为15m当量/千克（细胞水27m当量/升）时达到最高值。4. 研究了外部K⁺浓度对流出-含量关系的影响。发现增加K⁺浓度会通过提高饱和值来增加Na⁺流出，这与哈里斯（1965年）对青蛙肌肉的观察结果相似。5. 研究了增加外部二氧化碳浓度的影响。即使酵母悬浮液用100%二氧化碳平衡，也未注意到对Na⁺流出对数与Na⁺含量对数关系图斜率的影响。然而，用二氧化碳平衡溶液时，Na⁺流出量减少。