Strawn L M, Martell R E, Simpson R U, Leach K L, Counsell R E
Department of Medicinal Chemistry, University of Michigan, Ann Arbor 48109.
J Med Chem. 1989 Mar;32(3):643-8. doi: 10.1021/jm00123a024.
Analogues of diacylglycerol containing a 3-(3-amino-2,4,6-triiodophenyl)-2-ethylpropanoyl or 3-(3-amino-2,4,6-triiodophenyl)propanoyl group in the 2-position (1a and 1b, respectively) were synthesized and shown to compete with [3H]phorbol dibutyrate [( 3H]PDBu) for binding in a crude rat brain preparation. Phorbol diesters have been shown to bind specifically to protein kinase C and the PDBu receptor has been copurified with protein kinase C activity. The four diastereomers of 1a (1c-f) were synthesized from chiral starting material and studied in the same assay. The affinities for the [3H]PDBu binding site of 1a, 1b, and two isomers of 1a with naturally occurring L configuration were comparable to that of 1-oleoyl-2-acetyl-rac-glycerol (OAG), but the D isomers of 1a were essentially inactive. The chirality of the side chain did not influence the binding affinity. Activation of protein kinase C by 1a, 1c, and 1e demonstrated the same stereochemical requirements, but none were as active as OAG. For the 1,3-isomers 2, 2a, and 2b, the competitive binding studies gave different results. The racemic mixture and the D isomer, 2b, were able to compete for binding, but the L isomer, 2a, did not compete. These studies demonstrate that diacylglycerol binding to and activation of protein kinase C is stereospecific for the glycerol backbone, but not the side chain. Furthermore, the D-1,3-isomer must exist in a conformation such that the acyl and hydroxyl oxygens assume a spatial relationship similar to that in the L-1,2-isomers.
合成了在2-位分别含有3-(3-氨基-2,4,6-三碘苯基)-2-乙基丙酰基或3-(3-氨基-2,4,6-三碘苯基)丙酰基的二酰基甘油类似物（分别为1a和1b），并证明它们在大鼠脑粗提物中能与[3H]佛波醇二丁酸酯([3H]PDBu)竞争结合。佛波醇二酯已被证明能特异性结合蛋白激酶C，并且PDBu受体已与蛋白激酶C活性一起被共纯化。1a的四种非对映异构体(1c - f)由手性起始原料合成，并在相同的测定中进行研究。1a、1b以及两种具有天然L构型的1a异构体对[3H]PDBu结合位点的亲和力与1-油酰基-2-乙酰基-消旋甘油(OAG)相当，但1a的D异构体基本无活性。侧链的手性不影响结合亲和力。1a、1c和1e对蛋白激酶C的激活表现出相同的立体化学要求，但均不如OAG活性高。对于1,3-异构体2、2a和2b，竞争性结合研究给出了不同的结果。外消旋混合物和D异构体2b能够竞争结合，但L异构体2a不能竞争。这些研究表明，二酰基甘油与蛋白激酶C的结合及激活对甘油主链具有立体特异性，但对侧链没有。此外，D-1,3-异构体必须以一种构象存在，使得酰基和羟基氧原子呈现出与L-1,2-异构体中类似的空间关系。
