Electron probe studies of Na+ - K+-ATPase.

Use of appropriate reaction conditions allows direct quantitative measurements of the activity of Na-K-ATPase to be made with the electron probe microanalyzer. In addition, the demonstration by microanalysis of the linearity of the complete cytochemical reaction sequence is the first detailed analysis of the elemental sequence in a histochemical method and provides the basis for a visual semi-quantitative analysis of enzyme activity in tissue sections. This technique indicates the potential of electron probe microanalysis as a basic tool in enzymology.