Catalytic hydrogenolysis of poly-iodinated recombinant human insulin-like growth factor II (IGF-II): A potentially useful method for the tritiation of IGF-II

✍ Scribed by James A. Cook; William J. Wheeler; Gerald W. Becker; Michele C. Smith

• Publisher: Elsevier Science
• Year: 1991
• Tongue: English
• Weight: 624 KB
• Volume: 198
• Category: Article
• ISSN: 0003-2697
• DOI: 10.1016/0003-2697(91)90443-w

✦ Synopsis

A method has been developed to prepare, purify, and fully characterize poly-iodinated insulin-like growth factor II (IGF-II) which can then be catalytically deiodinated to produce IGF-II with its native disulfide bonded structure. This method can potentially be adapted to prepare tritiated IGF-II with the use of tritium gas in the hydrogenolysis step. IGF-II was iodinated at all three tyrosines using lactoperoxidase with a three-fold excess of sodium iodide. The iodinated products were purified using reversed-phase HPLC and characterized by peptide mapping. The tyrosine-containing peptides generated by pepsin digestion were characterized by amino acid sequence analysis. Mono- and di-iodinated phenylthiohydantoin tyrosine derivatives were synthesized and used to identify the iodination state of the modified tyrosine residues in the sequence analysis. Purified poly-iodinated IGF-II was deiodinated by hydrogenolysis, over a prereduced palladium (II) oxide catalyst to form IGF-II with its native disulfide bonds intact, as shown by peptide mapping.