Catalytic hydrogenolysis of poly-iodinated recombinant human insulin-like growth factor II (IGF-II): a potentially useful method for the tritiation of IGF-II.
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.
Cook
J A
JA
Virology Research, Eli Lilly and Company, Indianapolis, Indiana 46285-0444.
Wheeler
W J
WJ
Becker
G W
GW
Smith
M C
MC
D000595:Amino Acid Sequence; D002384:Catalysis; D006801:Humans; D006859:Hydrogen; D006868:Hydrolysis; D007335:Insulin-Like Growth Factor II / Q000737:chemistry* / Q000302:isolation & purification; D007455:Iodine / Q000737:chemistry; D008969:Molecular Sequence Data; D010165:Palladium / Q000737:chemistry; D010449:Peptide Mapping; D011994:Recombinant Proteins / Q000737:chemistry*; D014316:Tritium
D011994:Recombinant Proteins; D014316:Tritium; D010165:Palladium; D007335:Insulin-Like Growth Factor II; D006859:Hydrogen; D007455:Iodine