Estimation of Free Thiols and Disulfide Bonds Using Ellman’s Reagent

INTRODUCTION This protocol describes a method for quantitating the amount of free thiols and disulfide bond linkages in proteins. It uses the sulfhydryl reagent 5,5′-dithiobis (2-nitrobenzoic acid), or DTNB, which is also referred to as Ellman’s reagent.