title: Effect of high tyrosine content on the determination of tryptophan in protein by the acidic ninhydrin method. Application to chicken ovoinhibitor.
abstract: Colorimetric determination of tryptophan in intact proteins by the acidic ninhydrin method of Gaitonde & Dovey (1970) gives high apparent tryptophan contents for proteins having high tyrosine/tryptophan ratios. Correction for this interference by tyrosine can be achieved by plotting the ratio of observed to expected tryptophan content as a function of tyrosine/tryptophan ratio for proteins of known composition. The equation of the line is: [Formula: see text] Application of this correction to chicken ovoinhibitor, which contains 17 tyrosine residues per molecule, gave results that agree with tryptophan content determined by other methods.
mesh_terms: D000818:Animals; D002645:Chickens; D003124:Colorimetry; D007202:Indicators and Reagents; D007700:Kinetics; D009113:Muramidase / Q000032:analysis; D011506:Proteins / Q000032:analysis*; D012709:Serum Albumin / Q000032:analysis; D013053:Spectrophotometry; D014364:Tryptophan / Q000032:analysis*; D014443:Tyrosine / Q000494:pharmacology*
chemical_list: D007202:Indicators and Reagents; D011506:Proteins; D012709:Serum Albumin; D014443:Tyrosine; D014364:Tryptophan; D009113:Muramidase