<prompt> Ninhydrin test is used for -Bile saltsAmino acidsNucleic acidLipids  <response>: Ans. is b i.e., Amino acids Important chemicai reactions of amino acidso Folowing are some important chemical reactions.Reaction used to determine amino acid sequence in polypeptide chain : -Generally, amino terminal N-tenninal of amino acid is tagged with some reagent. It is split offby hydrolysis and tagged amino acid is identified. The reaction is, then, repeated with new N-terminal of subsequent amino acid and so on. The two reactions are used for identification of amino acid sequence : -Sangers reaction : - Uses Sangers reagent 1 -fluoro-2,4-dinitrobenzene to tag amino terminal.Edmans reaction : - Uses Edmans reagent phenylisothiocyanate to tag amino terminal.Reaction used to identification of individual or group of amino acids : - These reactions are frequently used for qualitative detection and quantitative measurement of various amino acids.Xin hydrin test0 : - All a-amino acids.Xanthophoretic reaction : - Aromatic amino acids Q Tyrosine, try ptophan, phenylalanine.Millans test Q Miilon-Nasse reaction: - Tyrosine Q phenol group of tyrosine. Therefore millons test is positive in tyrosinosis Q.Aldehyde test: - Tryptophan indole ringHopkins-cole reaction : - Tryptophan indole ringSakaguchs reaction : - Arginine guanidinium group of arginine.Sulphur test: - Cysteine sulphydryl groupNitroprusside test: - Cysteine sulphydryl groupPaulys test: - Histidine imidazole groupBiuret reaction : - Peptide bondDiazo reaction Q Paulis : - Histidine or tyrosine. 