D-Phe complexes of zinc and cobalt carboxypeptidase A.
D-Phe complexes of zinc and cobalt carboxypeptidase A.
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锌和钴羧肽酶 A 的 D-Phe 复合物。
DOI：
10.1016/0162-0134(96)00037-2
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发表时间：
1996
影响因子：
3.9
通讯作者：
Auld,DS
中科院分区：
文献类型：
--
作者：
Larsen,KS;Zhang,K;Auld,DS
用动力学和光谱技术研究了D-苯丙氨酸（D-Phe）与锌羧肽酶A（ZnCPD）和钴羧肽酶A（CoCPD）的结合。ZnCPD催化的D-Phe水解的动力学研究表明，在pH 8.4，1 M NaCl，25°C下，D-Phe抑制通过两个位点的顺序竞争性抑制模式发生，Ki值为45 μM和11.6 mM。在相同条件下CoCPD的光谱滴定表明D-Phe的结合模式非常强（KD< 100 μM），仅轻微干扰可见钴电子跃迁。然而，CoCPD · D-Phe转化为CoCPD ·D-Phe 2（KD，1.13 mM）伴随着非常强的光谱扰动，导致复合物的特征在于λ max值为506 nm（λ = 27 M−1cm−1）和605 nm（λ = 17 M−1cm−1），以及530 nm（λ = 23 M−1cm−1）处的肩峰。这种三元配合物的光谱性质与CoCPD · L-Phe · N3−三元配合物的光谱性质明显不同。X射线吸收精细结构（XAFS）研究表明，这些差异可能是由于与Zn和CoCPD·D-Phe 2配合物的八面体配位几何结构相比，三元叠氮配合物的四面体配位球更规则。
The binding of D-phenylalanine, D-Phe, to both zinc and cobalt carboxypeptidase A, ZnCPD and CoCPD, has been investigated by a combination of kinetic and spectroscopic techniques. Kinetic studies of the ZnCPD catalyzed hydrolysis of dansyl-Gly-Ala-L-Phe indicate that D-Phe inhibition occurs through a two-site sequential competitive inhibition mode with Kivalues of 45 μM and 11.6 mM at pH 8.4, 1 M NaCl, 25°C. Spectral titration of CoCPD under the same conditions indicates a very strong binding mode of D-Phe (KD< 100 μM) that only slightly perturbs the visible cobalt electronic transitions. However, the conversion of CoCPD · D-Phe into a CoCPD · D-Phe2(KD, 1.13 mM) is accompanied by a very strong spectral perturbation resulting in a complex that is characterized by λmaxvalues of 506 nm (ϵ = 27 M−1cm−1) and 605 nm (ϵ = 17 M−1cm−1) and a shoulder at 530 nm (ϵ = 23 M−1cm−1). The spectral properties of this tenary complex differ markedly from that of the CoCPD · L-Phe · N3−ternary complex. X-ray absorption fine structure, XAFS, studies indicate that these differences are likely due to a more regular tetrahedral coordination sphere for the ternary azide complexes compared to an octahedral coordination geometry for the Zn and CoCPD·D-Phe2complexes.