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Structure and Enzymatic Reaction Mechanism of Prenyltransferases

异戊二烯基转移酶的结构和酶反应机制

基本信息

批准号：
63580111
负责人：
KOYAMA Tanetoshi
金额：
$ 0.96万
依托单位：
TOHOKU UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1988
资助国家：
日本
起止时间：
1988 至 1989
项目状态：
已结题

项目摘要

1. On Farnesyl Diphosphate Synthase: The enzymatic reactivities of methylenediphosphonate analogues of the substrates of farnesyl diphosphate synthase showed that isopentenyl diphosphate is engaged in the enzymatic reaction as a metal-free form, whereas metal-complexed allylic substrates are the actual forms for the prenyltransferase. Both (S)- and (R)-4- methylfarnesols, Synthesized respectively from (E)- ard (Z)-3-methyl-3-pentenyl diphosphates by means of farnesyl diphosphate synthase reaction, were demonstrated to be of almost 100% enantiomeric purity.2. On Hexaprenyl Diphosphate Synthase from Micrococcus luteus B-P 26: The catalytic site of hexaprenyl diphosphate synthase is formed by cooperative interaction between the two essential components, A and B, and that cysteine and arginine residues on component B play important roles in the enzymatic activity. Formation of a stable 50-kDa complex of the two essential components of the enzyme, which represents the catalytically active s … More tate of this enzyme, is observed in the presence of inorganic pyrophosphate or one of the substrates, isopentenyl diphosphate br farnesyl diphosphate.3. On Undecaprenyl Diphosphate Synthase: The synthase reaction with (E)-3-methyl-3-pentenyl diphosphate proceeded in the same stereochemical manner as that with isopentenyl diphosphate, but it had a full stop at the stage where a single condensation of the C_6-homologue with an allylic primer is completed to form a chiral prenyl diphosphate with an extra methyl group at the 4-position. Kinetic experiments with (2Z,6E,10E)-4-methyl-geranylgeranyl diphosphate disclosed the topological capacity of the substrate-binding site of undecaprenyl diphosphate synthase.4. Polyprenyl Diphosphate Synthase from a Higher Plant: A polyprenyl diphosphate synthase catalyzing the formation of ficaprenyl-type Z,E-mixed polyprenyl diphosphates was partially purified from mulberry leaves, Morus bombysis. The stereochemistry of hydrogen elimination from the 2-position of isopentenyl diphosphate during the Z-prenyl chain formation was determined that the 2-pro-S hydrogen was lost. Less

1.关于法尼基二磷酸合成酶：亚甲基二膦酸类化合物对法尼基二磷酸合成酶底物的反应活性表明，异戊烯基二磷酸是以非金属形式参与酶反应的，而金属络合的烯丙基底物才是戊烯基转移酶的实际形式。以(E)-ARD(Z)-3-甲基-3-戊烯基二磷酸为原料，经法呢基二磷酸合成酶反应分别合成了(S)-和(R)-4-甲基法呢醇，其对映体纯度几乎为100%。黄微球菌B-P26六烯基二磷酸合成酶的研究：六烯基二磷酸合成酶的催化部位是由A和B两个必需组分协同作用形成的，B组分上的半胱氨酸和精氨酸残基在酶活性中起着重要作用。代表具有催化活性的S…的酶的两个基本成分形成一个稳定的50 kDa复合体在无机焦磷酸盐或底物之一的异戊烯基二磷酸和法尼基二磷酸盐存在下，该酶的活性更高。十一烯基二磷酸合成酶：与(E)-3-甲基-3-戊烯基二磷酸的合成反应与异戊烯基二磷酸以相同的立体化学方式进行，但在C_6同系物与烯丙基引发剂完成单次缩合生成手性亚丙基二磷酸的阶段终止。用(2Z，6E，10E)-4-甲基香叶基香叶基二磷酸进行动力学实验，揭示了十一烯基二磷酸合成酶底物结合部位的拓扑能力。来自高等植物的聚戊烯基二磷酸合成酶：从桑叶中部分纯化了一种催化形成无花果烯基Z，E混合型聚戊烯基二磷酸的聚戊烯基二磷酸合成酶。测定了Z-戊烯基链形成过程中异戊烯基二磷酸2-位脱氢的立体化学，2-原S氢消失。较少