苄基异喹啉类化合物与钙调素相互作用的荧光光谱研究

Studies on Fluorescence Spectra of the Interaction of Benzyli soquinoline Compounds and Camodulin

苄基异喹啉类化合物拮抗钙调素(CaM)并抑制依赖CaM的环核苷酸磷酸二酯酶(CaM-PDE)的活力;用荧光测定法可检测它们与钙调素的相互作用。 Ca^(2+)存在下蝙蝙葛碱(D_1)及其衍生物(D_(14))在激发波长340nm处最大发射波长分别为463和455nm,结合CaM后荧光量子产率增加两倍多。它们同CaM的结合均依赖于Ca^(2+)。 本文制备的丹磺酰基CaM(D-CaM)结合Ca^(2+)后荧光最大发射峰值兰移(518→508nm),荧光强度增加22％。在Ca^(2+)存在下小檗胺衍生物E_6能与CaM结合并淬灭Ca^(2+)-D-CaM荧光。 单苄基异喹啉类化合物86040、86045能淬灭CaM的酪氨酸残基的特征荧光。 实验表明,CaM结合D_(14)、E_6、86040和86045的kd值分别为1.3、1.8、9.5和15.7μmol/L,所观察的化合物与CaM的亲和力的大小与它们拮抗CaM,抑制CaM-PDE的酶活力相对应。

Benzylisoquinoline compounds antagonize calmodulin (CaM) and inhibit the activity of cyclic nucleotide phosphodiesterase which is CaM-dependent (CaM-PDE) . The interaction of these compounds and CaM can be studied by fluorescence measurement.Dauricine (D1) and its derivative (D14) produced emission spectra with λmax 463 and 455nm respectively at 340nm excitation in the presence of Ca2+.The fluorophores produced higher quantum field with fluorescence intensity increased by more than 2 fold after they bound to CaM, The binding of D1,D14 to CaM were all depended on Ca2+.Upon binding of Ca2+ to the dansylcalmodulin (D-CaM)we synthesyzed, the λmax of emission moved from 518nm to 508nm and the fluorescence intensity increased about 22%. Berbamine derivative E6 could bind to CaM and quench the fluorescence of D-CaM in the presence of Ca2+.Mono-benzylisoquinoline compounds 86040 and 86045 could quench the fluorescence of the tyrosine residues in CaM.The experiment showed that CaM bound D14,E6,86045 and 86040 with Kd values of 1.3, 1.8, 9.5 and 15.7 μmol/L respectively. The affinity between the observed compounds and CaM was in agreement with their ability to inhibit the activity of CaM-PDE.