Biological activity of oxidized and reduced iodinated bombesins.
A method is reported for preparing oxidized and reduced iodinated Tyr4-bombesin. Iodogen was used to iodinate Tyr4-bombesin and the reaction products were separated by reverse-phase HPLC. The peak of oxidized label was then reduced by incubation with 725 mM dithiothreitol at 80 degrees C (pH 8.0) for one hour and the reaction products separated by HPLC as before. The reduced but not oxidized peaks of 125I-Tyr4-bombesin stimulated amylase release from rat pancreatic acini in vitro. We conclude that oxidation of bombesin producing C-terminal methionine sulfoxide destroys the biological activity of the peptide and that this form of oxidation can be reversed.
Vigna
S R
SR
UCLA School of Medicine, Center for Ulcer Research and Education.
Giraud
A S
AS
Reeve
J R
JR
Walsh
J H
JH
D000681:Amylases / Q000378:metabolism*; D000818:Animals; D001839:Bombesin / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000494:pharmacology; D007202:Indicators and Reagents; D007457:Iodine Radioisotopes; D010084:Oxidation-Reduction; D010179:Pancreas / Q000201:enzymology*; D051381:Rats
D007202:Indicators and Reagents; D007457:Iodine Radioisotopes; C035891:bombesin, Tyr(4)-; D000681:Amylases; D001839:Bombesin