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The structure and function of prostaglandin F synthase. (a dual function enzyme)

前列腺素F合酶的结构和功能。

基本信息

批准号：
05670156
负责人：
WATANABE Kikuko
金额：
$ 1.34万
依托单位：
Osaka Bioscience Institute
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1993
资助国家：
日本
起止时间：
1993 至 1995
项目状态：
已结题

项目摘要

Prostaglandin (PG) F synthase is a monomeric protein, consisting of a 322-amino acid polypeptide with a Mr of 36,517 (1). PGF synthase has at least two isozymes of the lung and the liver types, and its primary structure shows high similarity with those of aldose and aldehyde reductases. These enzymes also present dual function which is the reduction of PGD_2 and PGH_2, and may show different biological activities on various tissues. To analyze the structure and biological function of dual function enzymes, we report PGF synthase on enzymatic properties, protein chemistry and immnological properties.1. The analysis on the structure of PGF synthase.(a) point mutation (i) "H48L mutant" The enzymatic activity was rapidly inactive for enzyme reaction. (ii) "Y5F mutant" PGD and H reductase activities were hardly detected. (iii) "H117N mutant" PGD reductase activity was not detected, and PGH reductase activity remained to 17%. (b) the role of C-terminal amino acid residues. (i) "deletion of 7 … More amino acid residues from C-terminus." PGD reductase activity remained to 20% and PGH reductase activity to 80%. (ii) "deletion of 15 amino acid residues from C-terminus." PGD and H reductase activities remained only 5%. ^<55>Tyr seems to be the active site of the reduction of PGD and H,^<117>His may be also localized near its active site, and ^<48>His is related to its active site. Moreover, the result of H117N mutant and that of the deletion of 7 amino acid residues suggest that the binding sites of PGD is different from that of PGH,and that C-terminal amino acid residues need to keep the tertially structure of both active sites.2. The analysis of functio of PGF synthasePGF synthase activity shows the highest in lung, and was localized in alveola interstitial cells and nonciliated epithelial cells in lung. Furthermore, by double immunofluorescence staining, anti-PGF synthase antibody labeled for cytoplasmic actin but not for a-smooth muscle actin suggesting that the PGF synthase-positive cells are "contractile interstitial cells (CICs)". These CICs is involved in hypoxic pulmonary vasoconstriction, and PGF synthase may be related to hypoxic pulmonary vasoconstriction.The expression of PGF synthase in the uterus increased at the late pregnancy at the diestrus. PGF production changes at the estrous cycle and increases at the term of pregnancy accompanied with the expression of uterine PGF synthase. Less

前列腺素F合成酶是一种单体蛋白，由322个氨基酸组成，Mr为36,517(1)。PGF合成酶至少具有肺型和肝型两种同工酶，其初级结构与醛糖还原酶和醛还原酶具有高度的相似性。这些酶还具有还原PGD_2和PGH_2的双重功能，并可能在不同组织中表现出不同的生物活性。为了分析双功能酶的结构和生物学功能，本文报道了PGF合成酶的酶学性质、蛋白质化学性质和免疫学性质。PGF合成酶的结构分析。(a)点突变(i)“H48L突变体”酶活性迅速失活，进行酶反应。（ii）“Y5F突变体”PGD和H还原酶活性几乎没有检测到。（iii）未检测到“H117N突变体”PGD还原酶活性，PGH还原酶活性维持在17%。(b) c端氨基酸残基的作用。(i)“从c端删除了7…多个氨基酸残基。”PGD还原酶活性保持在20%，PGH还原酶活性保持在80%。（ii）“从c端删除15个氨基酸残基。”PGD和H还原酶活性仅为5%。^<55>Tyr似乎是PGD和H还原的活性位点，^<117>His也可能定位在其活性位点附近，^< 48>His与其活性位点有关。此外，H117N突变体和7个氨基酸残基缺失的结果表明，PGD的结合位点与PGH不同，c端氨基酸残基需要保持两个活性位点的结构。PGF合成酶的功能分析显示，epgf合成酶活性在肺中最高，并定位于肺肺泡间质细胞和非纤毛上皮细胞。此外，通过双免疫荧光染色，抗PGF合酶抗体标记胞浆肌动蛋白而不标记a-平滑肌肌动蛋白，提示PGF合酶阳性细胞为“收缩间质细胞（CICs）”。这些CICs参与缺氧肺血管收缩，PGF合酶可能与缺氧肺血管收缩有关。PGF合酶的表达在妊娠晚期和妊娠晚期呈上升趋势。PGF的产生在发情周期发生变化，妊娠期增加，并伴有子宫PGF合成酶的表达。少