【摘要】 本文报导了用pH电位法在温度为37±0.1℃和离子强度为150mM/dm~3下研究了丙氨酸与铜、锌、镍、镉的二元和三元配合物稳定常数,并确定了各体系中配合物粒子的正确组成.ΔlgK和lgX值表明混合配合物比较稳定。配位离子分布图指出在生理条件下,这些配合物主要是以中性配合物的形式存在。这对于金属离子的透膜传输有重要意义。更多还原

【Abstract】 The binary and ternary stability constants of DL-α-Alaninc with Cu(Ⅱ),Zn(Ⅱ),Ni(Ⅱ) and Cd(Ⅱ) were determined by pH polcntiometric titration at 37±0.1℃ and ionic strength 150mM/dm3.Potentiomeinc data were treated with ZPLOT,MAGEC,MINIQUAD and ESTA programs.The compositions of complex species were ascertained in the complex equilibriums by selection of different chemical models.The lgK and lgX values indicate that the complexes with mixed li-gands were obviously more stable than the simple binary systems especially in the zinc-alaninate-histidinale-proton system.Distribution curves of the complex species show the continuity of stepwise cotnplexing in the formation of complexes.At physiological pH region these complexes,except cadium system,existed mainly in the form of neutral complexes which have biological significance in the transfer of metal ons acrossing the membrane.更多还原