Kaya K, Sano T
Environmental Chemistry Division, National Institute for Environmental Studies, Tsukuba, Ibaraki, Japan.
Chem Res Toxicol. 1998 Mar;11(3):159-63. doi: 10.1021/tx970132e.
When microcystin-LR was exposed to UV, three major nontoxic compounds were formed. These compounds were identified as [4(E),6(Z)-Adda5]- and [4(Z),6(E)-Adda5]microcystin-LR, which are geometrical isomers of the Adda [3-amino-9-methoxy-2,6,8-trimethyl-10-phenyl-4(E),6(E)-decadienoic acid] moiety of microcystin-LR, and a novel compound, tricyclo-Adda [(2S,3S,1'R,3'S,4'S,5'R,6'R,7'R)-3-amino-5-(4',6'-dimethyl-3'-methoxy tricyclo[5.4.0.0(1',5')]undeca-8',10'-dien-6'-yl)-2-methy l-4(E)-pentenoic acid]-containing microcystin-LR ([tricyclo-Adda5]microcystin-LR), which was formed by [2 + 2] addition between the benzene ring and the double bond at position 6-7 of the Adda moiety of the microcystin. The geometrical isomers were formed reversibly, and their equilibrium constants were almost the same. [Tricyclo-Adda5]microcystin-LR was also formed reversibly and was decomposed under UV light. These results suggest that the breakdown of microcystin-LR by UV irradiation proceeds via [tricyclo-Adda5]microcystin-LR.
当微囊藻毒素-LR暴露于紫外线下时，会形成三种主要的无毒化合物。这些化合物被鉴定为[4(E),6(Z)-Adda5]-和[4(Z),6(E)-Adda5]微囊藻毒素-LR，它们是微囊藻毒素-LR的Adda[3-氨基-9-甲氧基-2,6,8-三甲基-10-苯基-4(E),6(E)-癸二烯酸]部分的几何异构体，以及一种新型化合物，含三环-Adda[(2S,3S,1'R,3'S,4'S,5'R,6'R,7'R)-3-氨基-5-(4',6'-二甲基-3'-甲氧基三环[5.4.0.0(1',5')]十一碳-8',10'-二烯-6'-基)-2-甲基-4(E)-戊烯酸]的微囊藻毒素-LR([三环-Adda5]微囊藻毒素-LR)，它是由微囊藻毒素的Adda部分的苯环与6-7位双键之间的[2 + 2]加成形成的。几何异构体是可逆形成的，它们的平衡常数几乎相同。[三环-Adda5]微囊藻毒素-LR也是可逆形成的，并在紫外线下分解。这些结果表明，紫外线照射导致微囊藻毒素-LR的分解是通过[三环-Adda5]微囊藻毒素-LR进行的。
