Erythrocyte porphobilinogen synthase activity as an indicator of lead exposure in children.
Erythrocyte porphobilinogen synthase activity as an indicator of lead exposure in children.
复制标题
红细胞胆色素原合酶活性作为儿童铅暴露的指标。
作者：
J. Chisolm;D. Thomas;T. Hamill
欧洲标准化的方法测量卟啉原合酶（PBGS，EC 4.2.1.24）活性在外周红细胞中被广泛用于流行病学研究的低水平铅吸收。我们已经修改了它，包括与二硫苏糖醇（DTT）的激活。在全血铅浓度范围为0.29 - 1.93 μ mol/L的儿童中，我们发现以下统计学显著相关性（r）：血铅与未活化PBGS活性= -0.773（p小于0.005）;血铅与DTT激活的PBGS活性= -0.265（p小于0.005）;血铅与DTT活化/非活化PBGS活性的比值= +0.818（p小于0.005）。在DTT活化/非活化PBGS活性比为1时，这表明PBGS没有铅依赖性抑制，预测相应的血铅浓度为0.24 μ mol/L（50微克/L）。在血液系统疾病的个体中，DTT活化/非活化比率比非活化PBGS活性更好地预测了血铅浓度，并在很大程度上弥补了PBGS活性的高变异性。我们还描述了技术，以尽量减少污染的锌和铅，并稳定酶的活性在收集，运输，储存和分析样品。
The European standardized method for measuring porphobilinogen synthase (PBGS, EC 4.2.1.24) activity in peripheral erythrocytes is widely used in epidemiological studies of low-level Pb absorption. We have modified it to include activation with dithiothreitol (DTT). In children with concentrations of Pb in whole blood ranging from 0.29 to 1.93 mumol/L, we found the following statistically significant correlations (r): blood Pb vs nonactivated PBGS activity = -0.773 (p less than 0.005); blood Pb vs DTT-activated PBGS activity = -0.265 (p less than 0.005); blood Pb vs the ratio of DTT-activated/nonactivated PBGS activity = +0.818 (p less than 0.005). At a DTT-activated/nonactivated PBGS activity ratio of 1, which indicates no Pb-dependent inhibition of PBGS, a corresponding blood Pb concentration of 0.24 mumol/L (50 micrograms/L) would be predicted. In individuals with hematological disorders, the DTT-activated/nonactivated ratio better predicted blood concentration of Pb than did the nonactivated PBGS activity, and largely compensated for the high variability in PBGS activity. We also describe techniques to minimize contamination by Zn and Pb and to stabilize enzyme activity during collection, transport, storage, and analysis of samples.