镉(Ⅱ)-蛋白质衍生物的极谱吸附波与应用

Polarograhic Adsorptive Wave of Cadmium-Protein Derivant and Its Application

研究了镉 ( ) -蛋白质衍生物在氨基乙酸 -氢氧化钠缓冲介质中的极谱行为 ,提出了一种灵敏的蛋白质测定的新方法 .含有巯基或二硫键蛋白质在 0 .2 m ol/ L 氢氧化钠溶液中于沸水浴加热 5 min后 ,在 0 .4 m ol/ L 氨基乙酸 -氢氧化钠 (p H=9.8)缓冲介质中 ,与 1 .0× 1 0 - 4m ol/ L 镉 ( )溶液混合 ,反应产物在单扫描极谱上于 - 0 .5 7V(vs.SCE)处产生一个稳定的、灵敏的吸附还原波 .峰电流与牛血清白蛋白 (BSA)、人血清白蛋白 (HSA)的浓度在7.5× 1 0 - 1 0 ～ 3.0× 1 0 - 7m ol/ L范围内呈线性关系 ,BSA、HSA检测限均为 3.0× 1 0 - 1 0 m ol/ L ;与溶菌酶 (L yso)的浓度在 3.5× 1 0 - 9～ 1 .4× 1 0 - 6 m ol/ L范围内呈线性关系 ,L yso的检测限为 1 .4× 1 0 - 9m ol/ L .该法应用于人血清样品中蛋白质的直接测定 。

The polarographic behavior of cadmium protein derivant was studied by means of single sweep polarography and a new sensitive method for the determination of proteins presented. Protein with sulfhydryl or disulfide bond in 0.2 mol/L NaOH was heated in boiling water for 5 minutes, and mixed with 1.0 × 10 -4 mol/L Cd(Ⅱ) in a buffer solution of 0.4 mol/L Glycine NaOH (pH9.8). The reactive product gives a well defined reductive adsorption wave at - 0.57 V (vs.SCE). The height of derivative wave is proportional to the concentration of protein. At the optimal conditions, the peak height is linearly proportional to bovine serum albumin(BSA) or human serum albumin(HSA) concentration in the range of 7.5 × 10 -10 ～ 3.0×10 -7 mol/L ( r BSA = 0.999 2, and r HSA =0.999 8). The determination limit of BSA or HSA is 3.0×10 -10 mol/L . For lysozyme (Lyso), the concentration range is from 3.5×10 -9 to 1.4×10 -6 mol/L ( r Lyso =0.998 9) and the determination limit is 1.4×10 -9 mol/L . The method has been applied to the determination of protein in human serum albumin samples with satisfactory results. The electrode process has also been studied.