Dyrberg T, Billestrup N
J Immunol Methods. 1984 Jul 6;71(2):193-201. doi: 10.1016/0022-1759(84)90065-6.
Chloramine-T iodination of protein A from Staphylococcus aureus and gel electrophoretic purification of the iodination mixture results in a stable tracer of high specific and functional activity. Following repeated gel electrophoresis of the tracer only a single component was observed. The specific activity of the 125I-protein A was between 30 and 55 muCi/micrograms. The binding of 125I-protein A to rabbit immunoglobulin exceeded 90% and the tracer competed effectively with unlabelled protein A in binding to cells incubated with sera containing surface antibodies. Storage of the tracer for up to 46 weeks resulted in a moderate decrease in maximal binding to immunoglobulin (from 91% to 64%), in TCA precipitable radioactivity (from 97% to 80%) and an approx. 30% decrease in the ability to detect cell bound immunoglobulin. It is concluded that gel electrophoretic purification of 125I-protein A produces a tracer with a very long shelf life.
对来自金黄色葡萄球菌的蛋白A进行氯胺-T碘化，并对碘化混合物进行凝胶电泳纯化，可得到一种具有高比活性和功能活性的稳定示踪剂。对该示踪剂进行多次凝胶电泳后，仅观察到单一成分。125I-蛋白A的比活性在30至55μCi/μg之间。125I-蛋白A与兔免疫球蛋白的结合率超过90%，并且该示踪剂在与含有表面抗体的血清孵育的细胞结合中，能有效地与未标记的蛋白A竞争。将该示踪剂储存长达46周，其与免疫球蛋白的最大结合率出现中度下降（从91%降至64%），三氯乙酸可沉淀放射性（从97%降至80%），并且检测细胞结合免疫球蛋白的能力大约下降30%。得出的结论是，对125I-蛋白A进行凝胶电泳纯化可产生一种保质期很长的示踪剂。
