Effect of high tyrosine content on the determination of tryptophan in protein by the acidic ninhydrin method. Application to chicken ovoinhibitor.
Effect of high tyrosine content on the determination of tryptophan in protein by the acidic ninhydrin method. Application to chicken ovoinhibitor.
复制标题
高酪氨酸含量对酸性茚三酮法测定蛋白质中色氨酸的影响
作者：
J. Zahnley;J. G. Davis
用Gaitonde&Dovey(1970)的酸性吲哚三酮法比色测定完整蛋白质中的色氨酸，对于具有高酪氨酸/色氨酸比率的蛋白质来说，色氨酸的表观含量很高。对于已知组成的蛋白质，可以通过绘制观察到的色氨酸含量与预期色氨酸含量的比率作为酪氨酸/色氨酸比率的函数来实现对酪氨酸的这种干扰的校正。这条线的方程式是：[公式：见正文]将这一修正应用于鸡卵抑制物，每个分子含有17个酪氨酸残基，得到的结果与用其他方法测定的色氨酸含量一致。
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.