<prompt> In determining protein structure, mercaptoethanol is used to:Identify C-terminal residueDenature proteinReduce disulfide bondsOxidize disulfide bonds  <response>: Ans. C. Reduce disulfide bondsb-mercaptoethanol reduces disulfide bonds. Identification of C-terminus is by Carboxypeptidase C or Y which cleaves any C-terminal amino acid, carboxypeptidase B cleaves only Arg or Lys, carboxypeptidase A does not cleave Arg, Lys, or Pro. Denaturation is disruption of protein structure by adding chemicals or acidic or alkaline reagents, heat etc. 