Butt E, van Bemmelen M, Fischer L, Walter U, Jastorff B
Universität Bremen, Fachbereich Chemie, FRG.
FEBS Lett. 1990 Apr 9;263(1):47-50. doi: 10.1016/0014-5793(90)80702-k.
The activation of the cGMP-dependent protein kinase and cAMP-dependent protein kinase by the diastereomers of guanosine 3',5'-monophosphorothioate, (Sp)-cGMPS and (Rp)-cGMPS, and 8-chloroguanosine 3',5'-monophosphorothioate, (Sp)-8-Cl-cGMPS and (Rp)-8-Cl-cGMPS, was investigated using the peptide Kemptide as substrate. The (Sp)-diastereomers, which have an axial exocyclic sulfur atom, bound to the cGMP-dependent protein kinase and stimulated its phosphotransferase activity. In contrast, the (Rp)-isomers, which have an equatorial exocyclic sulfur atom, bound to the enzyme without stimulation of its activity. (Rp)-cGMPS and (Rp)-8-Cl-cGMPS antagonized the activation of the cGMP-dependent protein kinase with a Ki of 20 microM and 1.5 microM, respectively. (Rp)-cGMPS also antagonized the activation of cAMP-dependent protein kinase with a Ki of 20 microM. In contrast, (Rp)-8-cGMPS ws a weak inhibitor of the cAMP-dependent protein kinase with a Ki of 100 microM. (Rp)-8-Cl-cGMPS appears to be a rather selective inhibitor of the cGMP-dependent protein kinase and may be a useful tool for studying the role of cGMP in broken and intact cell systems.
使用肽段肯普肽作为底物，研究了鸟苷3',5'-单磷酸硫酯的非对映异构体（Sp）-cGMPS和（Rp）-cGMPS以及8-氯鸟苷3',5'-单磷酸硫酯（Sp）-8-Cl-cGMPS和（Rp）-8-Cl-cGMPS对环鸟苷酸依赖性蛋白激酶和环腺苷酸依赖性蛋白激酶的激活作用。具有轴向环外硫原子的（Sp）-非对映异构体与环鸟苷酸依赖性蛋白激酶结合并刺激其磷酸转移酶活性。相反，具有赤道环外硫原子的（Rp）-异构体与该酶结合但不刺激其活性。（Rp）-cGMPS和（Rp）-8-Cl-cGMPS分别以20μM和1.5μM的Ki拮抗环鸟苷酸依赖性蛋白激酶的激活。（Rp）-cGMPS也以20μM的Ki拮抗环腺苷酸依赖性蛋白激酶的激活。相比之下，（Rp）-8-cGMPS是环腺苷酸依赖性蛋白激酶的弱抑制剂，Ki为100μM。（Rp）-8-Cl-cGMPS似乎是环鸟苷酸依赖性蛋白激酶的一种相当有选择性的抑制剂，可能是研究环鸟苷酸在破碎和完整细胞系统中作用的有用工具。
