Abstract
The results of several tests and the characteristic morphological distribution of the enzymatic activity appeared to be in favor of the validity and specificity of the histochemical lead nitrate technique for alkaline and acid deoxyribonuclease (DNAse) detection. These tests included thermal inhibition, omission of substrate, use of different chemical inhibitors and the reproduction of histochemical staining on Coujard's slides. Most of these results were in conformity with the biochemical data gathered from literature. Topographically selective inhibition of alkaline or acid DNAse by different factors suggested that there might exist two kinds of alkaline or acid DNase--one cytoplasmic and the other one nuclear. The whole histochemical procedure produced relatively small loss of alkaline and acid DNAse activities as verified by biochemical methods.