Speaker
Dr
Chantal Houée-Levin
(Laboratoire de Chimie Physique, Université Paris Sud, 91405 Orsay, France)
Description
It is known that methionine residues are easily oxidized non enzymatically to their sulfoxide form, and it has been proposed that this process in conjunction with its repair by methionine sulfoxide reductases would be a protective mechanisms towards oxidative stress. However oxidation of methionine does not always lead to the sulfoxide and in addition the susceptibility to oxidation of Met residues in a protein does vary.
We have reinvestigated the oxidation of several peptides containing Methionine either in C- or N-terminal by OH radicals produced by radiolysis and by photolysis. In all cases we have identified the final products by MSn. in addition we have characterized the sulfoxide forms by Infra Red Multiple Photon Dissociation (IRMPD) coupled to MS. We show that Methionine sulfoxide is always formed albeit in various quantities. In addition other products were characterized. In oxidation photo-sensitized by benzophenone derivatives, adducts are formed. Thus the biological consequences of the oxidation of Methionine in oxidative stress must be revisited.
Primary author
Dr
Chantal Houée-Levin
(Laboratoire de Chimie Physique, Université Paris Sud, 91405 Orsay, France)
