ENZYMIC CONVERSION OF HYDROXYCINNAMIC ACIDS TO PARA-COUMARYLQUINIC AND CHLOROGENIC ACIDS IN TOMATO FRUITS
ENZYMIC CONVERSION OF HYDROXYCINNAMIC ACIDS TO PARA-COUMARYLQUINIC AND CHLOROGENIC ACIDS IN TOMATO FRUITS
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DOI：
10.1016/s0031-9422(00)84376-9
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发表时间：
1976-01-01
期刊：
影响因子：
3.8
通讯作者：
WOOLTORTON, LSC
中科院分区：
文献类型：
--
作者：
RHODES, MJC;WOOLTORTON, LSC
用离子交换层析法分离纯化了两种与绿原酸生物合成有关的酶，并对其性质进行了研究。这两种酶，对香豆酸CoA连接酶和羟基肉桂酰CoA：奎尼酸羟基肉桂酰转移酶，一起作用催化对香豆酸转化为5“-对香豆酰奎尼酸和咖啡酸转化为绿原酸。该连接酶对对香豆酸的亲和力高于对咖啡酸的亲和力，并且还将活化许多其它肉桂酸，例如阿魏酸、异阿魏酸和间香豆酸，但不活化肉桂酸。该转移酶对香豆酰CoA的活性和亲和力高于咖啡酰CoA。它也与阿魏酰辅酶A作用，但作用非常缓慢。该酶对奎尼酸具有高特异性;莽草酸仅以奎尼酸酯化率的2%酯化，葡萄糖不是底物。转移酶活性是可逆的，绿原酸和5“-对香豆酰奎尼酸在CoA存在下裂解形成奎尼酸和相应的羟基肉桂酰CoA硫酯。
Two enzymes thought to be involved in the biosynthesis of chlorogenic acid were separated and purified by ion exchange chromatography and their properties studied. These 2 enzymes, p-coumarate CoA ligase and hydroxycinnamyl CoA:quinate hydroxycinnamyl transferase, acting together catalyse the conversion of p-coumaric acid to 5''-p-coumarylquinic acid and of caffeic acid to chlorogenic acid. The ligase has a higher affinity for p-coumaric than for caffeic acid and will in addition activate a number of other cinnamic acids such as ferulic, isoferulic and m-coumaric acids but not cinnamic acid. The transferase shows higher activity and affinity with p-coumaryl CoA than caffeyl CoA. It also acts with ferulyl CoA but only very slowly. The enzyme shows high specificity for quinic acid; shikimic acid is esterified at only 2% of the rate with quinic acid and glucose is not a substrate. The transferase activity is reversible and both chlorogenic acid and 5''-p-coumarylquinic acids are cleaved in the presence of CoA to form quinic acid and the corresponding hydroxycinnamyl CoA thioester.