采用乳过氧化物酶法改进胰高血糖素的放射性碘化。pH对碘取代的影响。
Improved radioiodination of glucagon with the lactoperoxidase method. Influence of pH on iodine substitution.
作者信息
Von Schenck H, Larsson I, Thorell J I
出版信息
Clin Chim Acta. 1976 Jun 1;69(2):225-32. doi: 10.1016/0009-8981(76)90500-3.
To produce a 125I-labelled glucagon suitable for radioligand assays, we studied the influence of variations in the lactoperoxidase iodination method. Both the degree of iodine substitution and the formation of monoiodo- or diiodo-tyrosines were pH dependent. The substitution increased and the diiodo-/monoiodotyrosine ratio decreased when pH increased. These two factors affected the immunoreactivity of the iodoglucagon relatively independently of each other. It was found that iodination at pH 10.0 with an average of 0.3 gatom I/mol glucagon resulted in 125I-labelled glucagon with higher immunoreactivity and stability than that produced at the conventional pH 7.5 and 8.5.
为制备适用于放射性配体分析的125I标记胰高血糖素，我们研究了乳过氧化物酶碘化法中各种变化的影响。碘取代程度以及单碘酪氨酸或二碘酪氨酸的形成均依赖于pH值。当pH值升高时，取代增加，二碘酪氨酸/单碘酪氨酸比率降低。这两个因素对碘化胰高血糖素免疫反应性的影响相对独立。结果发现，在pH 10.0条件下，平均每摩尔胰高血糖素用0.3克原子碘进行碘化，所产生的125I标记胰高血糖素比在传统的pH 7.5和8.5条件下产生的具有更高的免疫反应性和稳定性。
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