OVOTHIOLS, A FAMILY OF REDOX-ACTIVE MERCAPTOHISTIDINE COMPOUNDS FROM MARINE INVERTEBRATE EGGS
OVOTHIOLS, A FAMILY OF REDOX-ACTIVE MERCAPTOHISTIDINE COMPOUNDS FROM MARINE INVERTEBRATE EGGS
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DOI：
10.1021/bi00387a043
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发表时间：
1987-06-30
期刊：
影响因子：
2.9
通讯作者：
SHAPIRO, BM
中科院分区：
文献类型：
--
作者：
TURNER, E;KLEVIT, R;SHAPIRO, BM
我们以前报道过一种新的硫醇化合物，1-甲基- n . α。, N.alpha。-二甲基-4-巯基组氨酸，或卵硫醇，高浓度存在于海海胆purpuratus的卵中[Turner， E., Klevit， R., Hopkins, p.b., and Shapiro， B.M.（1986）。化学学报，26(1),1356 - 1363。在这里，我们报告了两个相关的化合物，1-甲基- n .。-甲基-4-巯基组氨酸，或卵硫醇B，来自扇贝Chlamys hastata， 1-甲基-4-巯基组氨酸，或卵硫醇A，来自海星Evasterias troschelii。这两种化合物以及S. purpuratus化合物现在被命名为卵硫醇C，是通过[3H]碘乙酸的s -羧甲基化、离子交换色谱和离子配对高压液相色谱从卵子或卵巢组织中分离出来的。用1H NMR测定了S-（羧甲基）卵硫醇A和B的结构，用Raney镍脱硫后的卵硫醇A与正品甲基组氨酸样品的结构进行了比较。在每个物种的子房中，卵硫醇的主要甲基化形式至少占总4-巯基组氨酸的80%。卵巢的卵硫醇浓度远远超过睾丸或躯体组织。未受精卵卵硫醇C含量为1.14 μ。mol/106个卵，相当于4.3 mM左右的平均浓度；谷胱甘肽（GSH + GSSG）含量为0.9 .mu。摩尔/ 106个鸡蛋。在这个物种中，高卵硫醇水平在胚胎发育的前2周持续存在。卵硫醇和谷胱甘肽几乎占了鸡蛋中所有的三氯乙酸可溶性sh基团；这些结果与之前的几项研究进行了比较。卵硫醇A也未经事先烷基化分离得到；正如先前报道的卵硫醇C，它在空气中很容易氧化成二硫二聚体，并且还原形式赋予NAD(P)H-O2氧化还原酶对过氧化酶的活性，过氧化酶是一种在受精时胞外化的酶。一些实验观察表明，过度氧化酶/卵硫醇氧化酶活性不太可能是紫荆受精后“呼吸爆发”和H2O2产生的原因；另一种可能性是卵硫醇在控制H2O2毒性方面起作用。
We have previously reported a novel thiol compound, 1-methyl-N.alpha., N.alpha.-dimethyl-4-mercaptohistidine, or ovothiol, present at high concentration in the eggs of the sea urchin Strongylocentrotus purpuratus [Turner, E., Klevit, R., Hopkins, P.B., and Shapiro, B.M. (1986) J. Biol. Chem. 261, 13056-13063]. Here we report two related compounds, 1-methyl-N.alpha.-methyl-4-mercaptohistidine, or ovothiol B, from the scallop Chlamys hastata, and 1-methyl-4-mercaptohistidine, or ovothiol A, from the starfish Evasterias troschelii. These two compounds, as well as the S. purpuratus compound now designated ovothiol C, were isolated from eggs or ovarian tissue by S-carboxymethylation with [3H]iodoacetic acid, ion-exchange chromatography and ion-pairing high-pressure liquid chromatography. The structures of S-(carboxymethyl)ovothiols A and B were determined by 1H NMR, and that of ovothiol A was confirmed by comparison with authentic methylhistidine samples after desulfuration with Raney nickel. In the ovary of each species, the predominant methylation form of ovothiol accounts for at least 80% of the total 4-mercaptohistidine. The ovothiol concentration of the ovary far exceeds that of the testis or somatic tissues. The ovothiol C content of unfertilized S. purpuratus eggs is 1.14 .mu.mol/106 eggs, equivalent to approximately 4.3 mM average concentration; the glutathione (GSH + GSSG) content is 0.9 .mu.mol/106 eggs. In this species, high ovothiol levels persisted for the first 2 weeks of embryonic development. Ovothiol and glutathione accound for virtually all of the trichloroacetic acid soluble-SH groups in the egg; these results are compared to several previous studies. Ovothiol A was also isolated without prior alkylation; as previously reported for ovothiol C, it readily oxidizes in air to a disulfide dimer, and the reduced form confers NAD(P)H-O2 oxidoreductase activity on ovoperoxidase, an enzyme exocytosed at fertilization. Several experimental observations make it unlikely that the ovoperoxidase/ovothiol oxidase activity accounts for the "respiratory burst" and H2O2 generation that follow fertilization in S. purpuratus; an alternate possibility is that ovothiol functions in the control of H2O2 toxicity.