<prompt> Cysteine is abundantly found in:KeratinChondroitin S04CreatineSpermine  <response>: Ans: a Keratin Ref:Vasudevan, 4th ed, p.178; 5th ed, p. 191Cysteine is found in large quantities in keratin of hair and nails.Products of amino acids:TyrosineThyroid hormonesMelaninCatecholaminesThvptophanSerotoninMelatoninNADNADPArginineNitri oxideGlutamateGABAHistidineHistanineFIGLUOrnithine methionineSpermineSpermidineGlycineArginine MethionineCreatinine 