Sulfhydryl oxidation of reduced insulin in dilute solution.
The reduction of insulin by tri-n-butylphosphine followed by air oxidation in dilute solution at pH 9.1 yields A- and B-chain disulfides. A(S-S)2 and B(S-S) have been purified on SP-Sephadex C-25 using a linear gradient of sodium chloride from 0.1 to 0.45 M in 0.5 M acetic acid containing 7 M urea. The overall yield of A(S-S)2 was 70%; and B(S-S), 60%. The A(S-S)2 and B(S-S) had the expected amino acid composition and N-terminal amino acid. The kinetics of reduction and reoxidation of insulin disulfide bonds are discussed.
D000596:Amino Acids / Q000032:analysis; D000818:Animals; D002417:Cattle; D007202:Indicators and Reagents; D007328:Insulin; D007700:Kinetics; D010084:Oxidation-Reduction; D010720:Phosphines; D013438:Sulfhydryl Compounds / Q000032:analysis*
D000596:Amino Acids; D007202:Indicators and Reagents; D007328:Insulin; D010720:Phosphines; D013438:Sulfhydryl Compounds; C043255:tri-n-butylphosphine