Reaction Mechanism of Plant Polyketide Synthase

植物聚酮合酶的反应机理

• 批准号: 09672137
• 负责人: SHIBUYA Masaaki
• 金额: $ 1.86万
• 依托单位: The University of Tokyo
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1997
• 资助国家: 日本
• 起止时间: 1997 至 1998
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09672137/
• 关键词: p-coumaroyltriacetic acid synthase; p-coumaroyltriacetic acid lactone; Hydrangea macrophylla var. thunbergii; chalcone systhase; stilbene synthase; 反応機構; 還元酵素

Chalcone synthase (CHS) and stilbene synthase (STS) are plant-specific polyketide synthases (PKSs). They catalyze common three consecutive decarboxylative condensations and specific cyclization reactions. They are highly homologous to each other, and are likely to fall into a family of PKSs along with acridone synthase and bibenzyl synthase. Two cDNA clones (named as HmC and HmS) both of which show high homology to the known CHSs, were obtained from leaves of Hydrangea macrophylla var. thunbergii. They were expressed in Escherichia coli in order to determine their enzyme functions. Detection of chalcone formation clearly indicated that HmC encoded CHS, while HmS protein catalyzed the formation of neither chalcone nor stilbene. However, a novel pyrone, a lactonization product of a linear tetraketide was detected in reaction products of HmS protein. This proves that HmS encodes a novel PKS which catalyzes only chain elongation without cyclization.

查尔酮合酶（CHS）和芪合酶（STS）是植物特异性的聚酮化合物脱氢酶（PKS）。它们催化常见的三个连续脱羧缩合和特定的环化反应。它们彼此高度同源，并且可能与吖啶酮合酶和联苄基合酶一起沿着落入PKS家族。从绣球（Hydrangea macrophylla var.）叶片中获得了两个与已知的CHS具有高度同源性的cDNA克隆（命名为HmC和HmS）。雷鸣般的。它们在大肠杆菌中表达，以确定其酶功能。查耳酮形成的检测清楚地表明，HmC编码CHS，而HmS蛋白催化既不查耳酮也不芪的形成。然而，在HmS蛋白的反应产物中检测到一种新的吡喃酮，一种线性四酮化合物的内酯化产物。这证明HmS编码一种新的PKS，其仅催化链延长而不催化环化。

项目成果

Hiroyuki Morita, Hiroshi Noguchi, Takumi Akiyama, Masaaki Shibuya and Yutaka Ebizuka: "Chalcone Synthase from Scutellaria baicalensis" Towards Natural Medicine Research in the 21st Century, Excerpta Medica International Congress Series 1157, ed.by Hiroyuk

Hiroyuki Morita、Hiroshi Noguchi、Takumi Akiyama、Masaaki Shibuya 和 Yutaka Ebizuka：“来自黄芩的查耳酮合成酶”迈向 21 世纪的自然医学研究，医学摘录国际大会系列 1157，由 Hiroyuk 编辑

Takumi Akiyama, Masaaki Shibuya, and Yutaka Ebizuka: "cDNA clonig of polyketide synthases from Hydrangea macrophylla var." thunbergii, Towards Natural Medicine Research in the 21st Century, Excerpta Medica International Congress Series 1157, ed.by Hiroyuk

Takumi Akiyama、Masaaki Shibuya 和 Yutaka Ebizuka：“来自绣球花的聚酮合酶的 cDNA 克隆。”

T.Yamaguchi,: "Cross Reactions of Chalcone and Stilbene Synehoses" Towards Natural Medicine Research in the 21st Century,Excerpta Medica International Congress Series. 1157. 391-400 (1998)

T.Yamaguchi，：“查耳酮和二苯乙烯联苯的交叉反应”走向 21 世纪的自然医学研究，医学摘录国际大会系列。

H.Morita: "Chalcone Synthase from Scutellaria bacialensis" Towards Natural Medicine Research in the 21st Century,Exserpta Medica International Congress Series. 1157. 401-410 (1998)

H.Morita：“来自黄芩的查尔酮合成酶”走向21世纪的自然医学研究，Exserpta Medica国际大会系列。

Takumi Akiyama, Masaaki Shibuya, Hong-Min Liu and Yutaka Ebizuka: "p-Coumaroyltriacetic acid synthase, a new homologue of chalcone synthase, from Hydrangea macrophylla var. thunbergii" Eur.J.Biochem.submitted.

Takumi Akiyama、Masaaki Shibuya、Hong-Min Liu 和 Yutaka Ebizuka：“p-香豆酰三乙酸合酶，查耳酮合酶的新同源物，来自绣球花变种。”Eur.J.Biochem. 提交。