^125 I-3，3’-二碘甲腺原氨酸标记物的制备和鉴定

Preparation and identification of ^125 I labeled 3, 3＇-diiodothyronine

目的建立3，3＇-二碘甲腺原氨酸（3，3＇T2）的^125 I标记方法，并对标记产物进行鉴定。方法用氯胺T法以^125I标记3，3’T2；用Sephadex LH-20柱层析和下行纸层析纯化分离；以3，3’-T2纯品作为标准，通过下行纸层析、放射自显影、茚三酮显色等方法对标记产物进行鉴定。结果3，3＇-T2的^125 I标记率为26．57％，放化纯度为95．24％，比放射性为116μCi/μg，经Sephadex LH-20柱分离出现2个峰；标记产物下行纸层析分离后经放射自显影鉴定可见^125 I-rT3、^125I-3，3＇-T2、游离^125I，计算其Rf值分别为0．33、0．46、0．74；经下行纸层析、放射自显影、茚三酮显色的联合应用及标准品的对照证明Rf值0．46位置的物质就是^125I-3，3’T2。结论成功建立了3，3＇T2^125。I标记方法。

Objective To establish the method of ^125I labeling 3, 3＇-diiodothyronine and identify the labeled product. Methods 3, 3＇-diiodothyronine was labeled by ^125 I with chloramine-T method, purified and separated with Sephadex LH-20 column chromatography and descending paper chromatography, with pure 3, 3＇-T2 as standard preparation. Descending paper chromatography, radioautography and ninhydrin coloration were applied to identifying the labeled product. Results The ^125 I labeling rate of 3,3＇-T2 was 26.57%, the radiochemical purity of ^125 I-3,3＇-T2 was 95.24%, and the specific activity of ^125 I-3,3＇-T2 was 116 μCi per 1 μg protein. After separation by Sephadex LH-20 column chromatography, two peaks appeared. By means of descending paper chromatography and radioautography, the labeled products were identified as ^125 I-rT3, ^125 I-3, 3＇-T2 and free iodine; their Rf value was 0.33, 0.46 and 0.74 respectively. The product with Rf value of 0.46 was confired as ^125 I-3, 3＇- T2 by combined detection of descending paper chromatography, radioauography, ninhydrin coloration and standard control. Conclusion The method of ^125 I labeling of 3, 3＇-T2 is established successfully.