Hambright P, Langley R
Department of Chemistry, Howard University, Washington, D.C. 20059.
J Inorg Biochem. 1988 Mar;32(3):197-205. doi: 10.1016/0162-0134(88)80027-8.
The equilibrium and kinetic aspects of the interaction of cyanide with a model anticyanide drug cobalt(III)-tetrakis(4-sulfonatophenyl)porphyrin [Co-P] were studied at 25 degrees C, I = 0.1 (NaNO3). At the physiologic pH of 7.4, 1.9 +/- 0.1 mol of cyanide were rapidly bound per molecule of Co-P. The dissociation constant of cyanide from Co-P(H2O) (CN) was less than 10(-12), and the formation constant of Co-P(CN)2 from Co-P(H2O) (CN) and CN- was 3.5 X 10(6). From pH 4 to 10.5, the kinetics of mono-cyano Co-P formation were first order in cyanide and porphyrin, with the following specific rate constants (units M-1 s-1): Co-P(H2O)2/CN-, 3.1 X 10(2); Co-P(H2O) (OH)/CN-, 2.4 X 10(3); Co-P(OH)2/CN-, 5.1 X 10(1) and Co-P(H2O)/HCN, 3.1 X 10(-3). At pH 7.4, a second cyanide molecule adds more rapidly than the first: Co-P(H2O) (CN)/CN-, 3 X 10(4) M-1 s-1. It is concluded that low molecular weight water soluble cobalt(III) porphyrins might be used as effectively and at lower dose levels than hydroxocobalamin (B12b), a known in vivo anticyanide agent.
在25℃、离子强度I = 0.1（硝酸钠）的条件下，研究了氰化物与模型抗氰药物钴（III）-四（4-磺基苯基）卟啉[Co-P]相互作用的平衡和动力学方面。在生理pH值7.4时，每分子Co-P能迅速结合1.9±0.1摩尔的氰化物。氰化物从Co-P（H₂O）（CN）的解离常数小于10⁻¹²，而Co-P（CN）₂由Co-P（H₂O）（CN）和CN⁻形成的形成常数为3.5×10⁶。从pH 4到10.5，单氰基Co-P形成的动力学在氰化物和卟啉方面是一级反应，具有以下比速率常数（单位为M⁻¹ s⁻¹）：Co-P（H₂O）₂/CN⁻，3.1×10²；Co-P（H₂O）（OH）/CN⁻，2.4×10³；Co-P（OH）₂/CN⁻，5.1×10¹和Co-P（H₂O）/HCN，3.1×10⁻³。在pH 7.4时，第二个氰化物分子比第一个添加得更快：Co-P（H₂O）（CN）/CN⁻，3×10⁴ M⁻¹ s⁻¹。得出的结论是，低分子量水溶性钴（III）卟啉可能比已知的体内抗氰剂羟钴胺素（B12b）更有效且剂量更低。
