The effect of histidine and cysteine on the initial rate of zinc influx into rat and human erythrocytes in the presence of bovine serum albumin has been investigated. 2. The L-enantiomers of both amino acids promoted zinc influx into rat erythrocytes in a dose-dependent manner. L-Histidine, but not L-cysteine, also promoted zinc uptake into human erythrocytes. D-Histidine did not promote zinc uptake in either rat or human erythrocytes. In rat erythrocytes D-cysteine was significantly less effective than L-cysteine. 3. The stimulation of zinc influx into rat erythrocytes by 20 mM L-histidine was approximately 4.1 times that seen with human erythrocytes. 4. The influx of zinc in the presence of varying concentrations of L-histidine was linearly related to the calculated concentration of the zinc-bis-histidine complex but not to that of the zinc-mono-histidine complex or the free ionic zinc concentration. 5. These results are discussed in relation to the nature of the transport mechanisms involved.
摘要
研究了在牛血清白蛋白存在的情况下，组氨酸和半胱氨酸对锌流入大鼠和人红细胞初始速率的影响。2. 两种氨基酸的L-对映体均以剂量依赖性方式促进锌流入大鼠红细胞。L-组氨酸而非L-半胱氨酸也促进锌摄取进入人红细胞。D-组氨酸在大鼠或人红细胞中均不促进锌摄取。在大鼠红细胞中，D-半胱氨酸的效果明显低于L-半胱氨酸。3. 20 mM L-组氨酸对大鼠红细胞锌流入的刺激作用约为人红细胞的4.1倍。4. 在不同浓度L-组氨酸存在下锌的流入与计算出的双组氨酸锌络合物浓度呈线性相关，但与单组氨酸锌络合物或游离离子锌浓度无关。5. 结合所涉及的转运机制的性质对这些结果进行了讨论。
