GLUTACONATE COA-TRANSFERASE FROM ACIDAMINOCOCCUS-FERMENTANS
GLUTACONATE COA-TRANSFERASE FROM ACIDAMINOCOCCUS-FERMENTANS
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DOI：
10.1111/j.1432-1033.1981.tb06404.x
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发表时间：
1981-01-01
期刊：
影响因子：
--
通讯作者：
SEMMLER, R
中科院分区：
文献类型：
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作者：
BUCKEL, W;DORN, U;SEMMLER, R
A.发酵菌戊烯二酸CoA转移酶催化CoAS-从乙酰CoA优先转移到（E）-戊烯二酸，但戊二酸、（R）-2-羟基戊二酸、丙烯酸酯和丙酸酯也是良好的受体。未观察到与（Z）-戊烯二酸酯和C4-二羧酸的反应。乙酰辅酶A与（E）-戊烯二酸的反应产物是戊烯二酰辅酶A的1-异构体，即，硫羟酸酯与双键共轭。以（R）-2-羟基戊二酸为底物，生成两种可能的异构体。从A.发酵至表观均匀并结晶。该酶的相对分子质量为aptx。275,000.它由两条不同的多肽链组成（MW 32，000和34，000）。在催化途径上，在CoASH和较小多肽链的羧酸酯之间形成硫酯。讨论了戊烯二酸CoA转移酶与其他CoA转移酶之间的结构和功能关系。戊烯二酸CoA-转移酶也存在于通过羟基戊二酸发酵谷氨酸的其他细菌中。用抗该酶的抗血清进行的实验表明，该转移酶是戊烯二酸脱羧所必需的，但不是（R）-2-羟基戊二酸脱水所必需的。
A. fermentans glutaconate CoA-transferase catalyzes the transfer of CoAS- from acetyl-CoA preferentially to (E)-glutaconate, but glutarate, (R)-2-hydroxyglutarate, acrylate and propionate are also good acceptors. No reaction was observed with (Z)-glutaconate and C4-dicarboxylic acids. The product of the reaction of acetyl-CoA with (E)-glutaconate is the 1-isomer of glutaconyl-CoA, i.e., the thiol ester is conjugated with the double bond. With (R)-2-hydroxyglutarate as substrate, both possible isomers are generated. Glutaconate CoA-transferase was purified from cell-free extracts of A. fermentans to apparent homogeneity and crystallized. The relative molecular mass of the enzyme is .apprx. 275,000. It consists of 2 different polypeptide chains (MW 32,000 and 34,000). On the catalytic pathway a thiolester is formed between CoASH and a carboxylate of the smaller polypeptide chain. The structural and functional relationships between glutaconate CoA-transferase and other CoA-transferases are discussed. Glutaconate CoA-transferase is also present in other bacteria fermenting glutamate via hydroxyglutarate. Experiments with an antiserum against the enzyme indicate that the transferase is necessary for the decarboxylation of glutaconate but not for the dehydration of (R)-2-hydroxyglutarate.