<prompt> Tripeptide used for oxidation-raduction reaction -CreatinineGlutathioneMelaninNone  <response>: Ans. is b i.e., Glutathione o Glutathione is a tripeptide0 made up of glutamate, cysteine and glycine y-glutamyl-cysteiny 1-glycine.o Glutathione is present in all mammalian cells except neurons.o The sulphydryl -SH group of cysteine residue0 is the reactive portion of glutathione which can undergo oxidation and reduction.o Thus, glutathione may exist as the reduced G-SH or oxidized form G-S-S-G and can play a role in some oxidation- reduction reactions.o In oxidized form two molecules of glutathione are linked by disulfide bond. 