NOVEL REAGENT, METHOD, AND KIT FOR THE QUANTITATION OF OXIDATION-REDUCTION PHENOMENA IN PROTEINS AND PEPTIDES

摘要

A first embodiment of the method is for analyzing the amount of methionine sulfoxide in a protein sample and includes the steps of contacting a protein solution with methionine sulfoxide reductase in the presence of a reducing reagent bearing a covalently-linked reporter tag, whereby the reducing reagent is oxidized. The oxidized reducing reagent formed, which is proportion to the amount of methionine sulfoxide in the sample, is then quantified. A second embodiment of the method is for analyzing the amount of disulfide linkages in a polypeptide or protein sample. It proceeds in the same fashion as above, but in the absence of any enzyme. A novel fluorescently-labeled reducing agent, and kits to practice the method are also disclosed.