Biosynthesis of maturation-inducing hormone (1-methyladenine) by starfish ovarian follicle cells and its relation to cell adhesion factor

1.1-甲基腺嘌呤的生物合成为了确定海星卵泡细胞1-甲基腺嘌呤(1-mea)生物合成的可能底物，使用了甲硫氨酸、[U-^&lt；14&gt；C]腺苷和[U-^&lt；14&gt；C]腺苷。发现1-MeA的直接甲基供体是S-腺苷蛋氨酸，1-MeA的腺嘌呤分子来自ATP。虽然1-MeA的部分合成也是由SAM通过热处理得到的，但对体内甲基化相关的酶系统的进一步研究将为进一步了解海星卵泡细胞1-MeA的生物合成提供新的视角。2.1-甲基腺嘌呤的产生和细胞黏附因子作为一种细胞黏附因子，从海星卵泡细胞中部分纯化得到依赖于外向ATP二磷酸水解酶(ATPDase)。胞外ATPDase位于细胞表面，其相对分子质量约为6万。该酶可能在卵子发生过程中保护卵母细胞免受吞噬细胞和寄生虫的侵害。其他：新合成了10个N^1-取代的腺嘌呤衍生物。提示腺嘌呤N^1位点的区域特异性结构与卵母细胞中1-MeA受体的结合有关。与海星卵母细胞成熟相比，青海稻卵母细胞中存在几种GiAlpha亚单位蛋白。在卵母细胞成熟过程中，Gipha蛋白减少，排出的卵子中不存在GiAlpha蛋白。

1. Biosynthesis of 1-methyladenineTo determine possible substrates of 1-methyladenine (1-MeA) biosynthesis in starfish ovarian follicle cells, [methyl-^<14>C] methionine, [U-^<14>C] adenine and [U-^<14>C] adenosine were used. A direct methyl donor was found to be S-adenosylmethionine and the adenine molecule of 1-MeA to be drived from ATP.Although 1-MeA was also shown to be synthesized partially from SAM by heat tratment, further studies on the enzyme system related to the methylation in vivo should be provide additional insight into 1-MeA biosynthesis in starfish ovarian follicle cells.2.1-Methyladenine production and cell adhesion factorAs a cell adhesion factor, Mg^<2+>-dependent ecto-ATP diphosphohydrolase (ATPDase) was partially purified from starfish ovarian follicle cells. The ecto-ATPDase was located in cell surface and its molecular weight was about 60,000. It is probable that the ecto-ATPDase is responsible for protection of oocytes from phagocytes and parasites during oogenesis.Others : Ten N^1-substituted adenine derivatives were newly synthesized. It was suggested that regional specific structures of the N^1-site of adenine are related to binding with 1-MeA receptors in oocytes. Comparing with starfish oocyte maturation, several Gialpha subunit proteins were identified in medaka (Oryzias latipes) oocytes. During oocyte maturation, Gialpha proteins decreased and were absent in ovulated eggs.