Peters W H, Fleuren-Jakobs A M, De Pont J J, Bonting S L
Biochim Biophys Acta. 1981 Dec 21;649(3):541-9. doi: 10.1016/0005-2736(81)90158-9.
(1) The neutral lipids and the free and bound fatty acids of a highly purified (Na+ + K+)-ATPase preparation from rabbit kidney outer medulla have been analysed. (2) On a dry weight basis, the total lipid content is nearly the same as the total protein content, and consists for 66% of phospholipids and for 34% of neutral lipids and free fatty acids. In the latter category cholesterol is the main component (71%). (3) On a molar basis the enzyme preparation contains 382 mol phospholipids, 67 mol free fatty acids, 9, 16 and 12 mol mono-, di- and triacylglycerols, 249 and 19 mol free and esterified cholesterol per mol enzyme. (4) The fatty acid composition of each lipid and of the free fatty acid fraction, present in the enzyme preparation, is reported. (5) All cholesterol and part of the phospholipids can be removed by hexane extraction, leaving 66% of the (Na+ + K+)-ATPase activity. Oxidation of all cholesterol to cholest-4-en-3-one by cholesterol oxidase leaves 85% of the (Na+ + K+)-ATPase activity. These results indicate that cholesterol is not essential for (Na+ + K+)-ATPase activity.
(1) 对从兔肾外髓质高度纯化的（Na⁺ + K⁺）-ATP酶制剂中的中性脂质以及游离和结合脂肪酸进行了分析。(2) 以干重计，总脂质含量与总蛋白质含量几乎相同，其中磷脂占66%，中性脂质和游离脂肪酸占34%。在后一类中，胆固醇是主要成分（71%）。(3) 以摩尔计，酶制剂每摩尔酶含有382摩尔磷脂、67摩尔游离脂肪酸、9、16和12摩尔单酰甘油、二酰甘油和三酰甘油、249摩尔游离胆固醇和19摩尔酯化胆固醇。(4) 报道了酶制剂中每种脂质以及游离脂肪酸部分的脂肪酸组成。(5) 通过己烷萃取可去除所有胆固醇和部分磷脂，剩余66%的（Na⁺ + K⁺）-ATP酶活性。用胆固醇氧化酶将所有胆固醇氧化为胆甾-4-烯-3-酮后，剩余85%的（Na⁺ + K⁺）-ATP酶活性。这些结果表明胆固醇对于（Na⁺ + K⁺）-ATP酶活性并非必不可少。
