Identification of L-methionine oxidation products in tripeptides, in Met-enkephalin and in the bovine basic pancreatic trypsin inhibitor: 1H and 13C NMR study.
L-methionine (Met) oxidation products in tripeptides, in Met-enkephalin and in the bovine basic pancreatic trypsin inhibitor have been identified by 1H and 13C NMR spectroscopy. The oxidation of Met residues by stoichiometric amounts of chloramine-B, H2O2 and I2 yields a mixture of L-methionine sulfoxide (Met (O)) and dehydro-L-methionine (DH-Met), Met (O) and DH-Met, respectively, at pH 7.0 and 25.0 degrees C. The formation of DH-Met occurs only if the amino-group of Met is not derivatized. The analysis of 1H and 13C NMR spectra allows us to quantitate Met oxidation products, to ascertain the relative proportion of the R and S forms of Met (O) and DH-Met, and to reveal the presence of a Met residue at the N-terminal position in peptides and proteins.
Fruttero
R
R
Dipartimento di Scienza e Tecnologia del Farmaco, Università di Torino, Italy.
Amiconi
G
G
Ascoli
F
F
Bolognesi
M
M
Ascenzi
P
P
D000818:Animals; D007611:Aprotinin / Q000378:metabolism*; D002247:Carbon Isotopes; D002417:Cattle; D004744:Enkephalin, Methionine / Q000737:chemistry*; D006859:Hydrogen; D009682:Magnetic Resonance Spectroscopy; D008715:Methionine / Q000031:analogs & derivatives / Q000032:analysis / Q000737:chemistry*; D009842:Oligopeptides / Q000737:chemistry*; D010084:Oxidation-Reduction; D013237:Stereoisomerism; D013844:Thiazoles / Q000032:analysis / Q000737:chemistry
D002247:Carbon Isotopes; D009842:Oligopeptides; D013844:Thiazoles; C057796:dehydromethionine; D004744:Enkephalin, Methionine; D006859:Hydrogen; D007611:Aprotinin; D008715:Methionine; C013111:methionine sulfoxide