A QUANTITATIVE STUDY OF THE FEULGEN REACTION WITH THE AID OF HISTOCHEMICAL MODEL SYSTEMS

Abstract

This paper reports some quantitative results with three histochemical model systems. The model systems are DNA-cellulose, deoxyadenylic acid-cellulose and deoxyguanylic acid-cellulose, and DNP-bovine albumin-polyacrylamide. By measuring the UV-absorption of the nucleotide-cellulose after various hydrolysis times, the rates of splitting-off of the purines by HCl were determined. Adenine is found to be split off twice as fast as guanine. The phosphorus/pararosaniline ratio is found to differ considerably from the theoretical value calculated on the assumption that every free aldehyde group reacts with pararosaniline. The differences in the values found for the phosphorus/pararosaniline ratio of the DNA-cellulose and the nucleotide-cellulose can be related to the differences in the absorption spectra of these models, which points to different degrees of substitution at the amino groups of pararosaniline. Addition of protein to DNP in a polyacrylamide film does not alter the phosphorus/pararosaniline ratio.