Papp S, Rutzke M, Martonosi A
Arch Biochem Biophys. 1985 Nov 15;243(1):254-63. doi: 10.1016/0003-9861(85)90794-5.
Treatment of sarcoplasmic reticulum vesicles with ethylene glycol bis(beta-aminoethyl ether)-N,N'-tetraacetic acid (EGTA), Chelex-100, 1,10-phenanthroline, 8-hydroxyquinoline, or 8-hydroxyquinoline sulfonic acid increases the reactivity of SH groups with N-(1-pyrene)maleimide (PMI). The effect of Chelex treatment can be reversed by the addition of 10(-6)-10(-5) M Zn2+ to the Chelex-treated microsomes. The activation of the PMI reaction by EGTA was not reversed by subsequent addition of calcium, although the presence of excess calcium during EGTA treatment abolished the effect. Analysis of the elemental composition of sarcoplasmic reticulum by plasma emission spectroscopy indicates the presence of Zn, Cu, Fe, and Hg in amounts of 1-2 nmol/mg protein; of these only the Zn content is reduced significantly by treatment of microsomes with EGTA or Chelex-100. These observations suggest that Zn2+ may play a role in the regulation of the reactivity of SH groups in sarcoplasmic reticulum either by direct interaction with cysteinyl residues or by an effect upon the conformation of a subpopulation of ATPase molecules.
用乙二醇双（β-氨基乙醚）-N，N'-四乙酸（EGTA）、螯合树脂-100、1,10-菲咯啉、8-羟基喹啉或8-羟基喹啉磺酸处理肌浆网囊泡，可增加SH基团与N-（1-芘）马来酰亚胺（PMI）的反应活性。用螯合树脂处理后的效果可通过向经螯合树脂处理的微粒体中添加10⁻⁶ - 10⁻⁵ M Zn²⁺来逆转。EGTA对PMI反应的激活作用不会因随后添加钙而逆转，尽管在EGTA处理期间存在过量钙会消除这种作用。通过等离子体发射光谱法分析肌浆网的元素组成表明，其含有1 - 2 nmol/mg蛋白质的锌、铜、铁和汞；其中只有锌含量会因用EGTA或螯合树脂-100处理微粒体而显著降低。这些观察结果表明，Zn²⁺可能通过与半胱氨酰残基直接相互作用或通过对ATP酶分子亚群构象的影响，在调节肌浆网中SH基团的反应活性方面发挥作用。
