Department of Agronomy, University of Kentucky, Lexington.
Planta. 1968 Sep;83(3):314-22. doi: 10.1007/BF00385341.
Mitochondria, isolated from potato tuber, pretreated with ribonuclease (RNase) showed an increase in calcium binding at low enzyme concentration. The same dosage-response pattern was obtained whether the enzyme treatment was conducted for 10, 30 or 120 min. However, when the enzyme treatment was carried out at 0° instead of at 30°, no increase in Ca-binding was obtained, suggesting that no interaction occurred between the enzyme and the divalent cation. Oxygen consumption under the same conditions was not affected. Microsomes treated with RNase did not show a change in their Ca-binding capacity, although untreated microsomes showed about the same increase in Ca-binding with increase in temperature as did the mitochondria. When mitochondria prelabeled with (45)Ca, after extracting their inorganic calcium phosphate, were treated with RNase a liberation of Ca, ribonucleotide, and phosphate was observed. It is suggested that Ca ions form a bridge like bond between ribonucleic acid and either phospholipids or phospholipoproteins, because RNase liberated more phosphate than nucleotides and the extra phosphate cannot be inorganic calcium phosphate, since the calcium phosphate was extracted before addition of RNAse.
从土豆块茎中分离出来的线粒体，用核糖核酸酶（RNase）预处理后，在低酶浓度下显示出钙结合增加。无论酶处理进行 10、30 或 120 分钟，都可以获得相同的剂量反应模式。然而，当酶处理在 0°C 而不是 30°C 进行时，没有观察到钙结合增加，这表明酶和二价阳离子之间没有相互作用。在相同条件下，耗氧量不受影响。用核糖核酸酶处理的微粒体没有显示出钙结合能力的变化，尽管未经处理的微粒体在增加温度时与线粒体一样显示出相同的钙结合增加。当用 (45)Ca 预先标记的线粒体，在提取其无机磷酸钙后，用核糖核酸酶处理时，观察到 Ca、核糖核苷酸和磷酸盐的释放。这表明 Ca 离子在核糖核酸和磷脂或磷脂蛋白之间形成桥连键，因为 RNase 释放的磷酸盐多于核苷酸，并且额外的磷酸盐不可能是无机磷酸钙，因为在添加 RNAse 之前已经提取了磷酸钙。
