Influence of Triton X-100 on Protein Determination by Lowry Procedure

Abstract

Although the presence of Triton X-100 [TX-100], a commonly used surface active agent, affects both the intercept and the slope of the calibration curve in the Lowry method of protein determinations, absorbance in the presence of TX-100 is still proportional to protein concentration. In the presence of TX-100 an increasing concentration of TX-100 decreased the absorbance depending on the protein [bovine serum albumin] content except for the enhancement observed at low concentration of TX-100. The maximum enhancement of absorbance by the addition of TX-100 was at a concentration in the region of 0.25% TX-100. In the absence of protein the increasing concentrations of TX-100 linearly increased absorbance. Although the presence of TX-100 affected the calibration curve slope, absorbance in the presence of TX-100 was still proportional to protein concentration. The problem in protein estimation by Lowry method in the presence of TX-100 was easily circumvented by using a standard calibration curve made by adding to each standard sample the same amount of TX-100 as present in the experimental samples.