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在高氯酸介质和160℃温度下,~(211)At和~(131)I能直接通过亲电取代反应成功地标记在酪氨酸分子上,采用阴离子交换色层分离酪氨酸,纸层析显色分析和作γ放射性扫描测定出标记产额。~(211)At标记酪氨酸的产额高达95％以上,~(131)I的标记率为50％。标记结果的差异正是At和I两个元素性质差异的表现,At的氧化条件要比I温和。~(211)At可以在高氯酸和醋酸的混合酸中标记,而~(131)I只能在纯的高氯酸体系中标记。用H_2O_2和氯胺T作氧化剂,以适合~(211)At和~(131)I标记蛋白质的条件标记酪氨酸,结果都只得到极低的产额。说明蛋白质和酪氨酸的标记有很大的差别。
In the medium of perchloric acid and temperature of 160 ℃, ~ (211) At and ~ (131) I can be directly labeled on tyrosine by electrophilic substitution reaction, and anion exchange chromatography is used to separate tyrosine, Chromatographic chromogenic analysis and gamma radioactive scans were performed to determine the marker yield. The yield of ~ (211) At-labeled tyrosine was over 95%, and the labeling rate of ~ (131) I was 50%. The difference between the labeled results is the difference between the two elements of At and I. The oxidation condition of At is milder than I. ~ (211) At can be labeled in the mixed acid of perchloric acid and acetic acid, whereas ~ (131) I can only be labeled in the pure perchloric acid system. With H 2 O 2 and chloramine T as oxidants, tyrosine was labeled under conditions suitable for ~ (211) At and ~ (131) I labeling of proteins, resulting in very low yields. There is a big difference between the labeling of protein and tyrosine.