CYTOFLUOROMETRIC DETERMINATION OF BASIC AND TOTAL PROTEINS WITH SULFAFLAVINE

The cytofluorometric determination of histones and total proteins with a single acid dye, Sulfaflavine, at the pHs 8.0 and 2.8, is described. Successive staining and measuring at the two pHs allow the determination of histones and total proteins in individual cells. Optimal staining conditions were determined; the specificity and the linearity of the staining were confirmed in model experiments (protein smears) and with different kinds of cells. The protein smears also served for calibration in absolute terms; the obtained protein values agreed with those calculated from dry weight measurements and with values from the literature. The influence of fixation (formalin and ethanol-acetic acid) and preparation, the reproducibility of the staining reaction and the inherent limitations of the method are discussed.