A modification of the amidoblack-TCA-staining for quantitative microspectrometrical determination of proteins in tissue sections.

Conditions are described by which cells and fresh frozen tissues, following fixation with ethanol-ether, and after staining with the amidoblack (AB)-TCA-staining method, show a modified dye/protein ratio of 0.9 moles AB/10(5) g protein compared to 8.5 moles AB/10(5) g protein ( Schauenstein et al. 1980) as in a previously used method. In contrast to the AB-TCA-method, which leads to extremly high and unmeasurable extinctions in tissue sections, staining with the modified AB-TCA- 23st -method with 10 microns tissue sections produces easily measurable extinction values. A correlation of the microspectrometrically determined mean total extinction values of different cell types and nuclei after staining with the tetrazonium method (N ohammer 1978; N ohammer and Desoye 1981) and on the other hand with the AB-TCA 23st -method has been found. The microspectrometrically determined extinctions after AB-TCA 23st -staining can be calculated; an extinction of 0.04248 corresponds to 1 pgm protein.