Quantitative aspects of the cytochemical demonstration of glucose-6-phosphate dehydrogenase with tetrazolium salts studied in a model system of polyacrylamide films

The enzyme cytochemical demonstration of glucose-6-phosphate dehydrogenase (G6PDH) with several tetrazolium salts has been studied with an artificial model of polyacrylamide films in corporated with the enzyme, which enabled teh correlation of cytochemical and biochemical data. In the model films no formazan could be produced with BPST and NT in contrast to NBT and TNBT. The reason of this phenomenon is discussed. The concentration of acrylamide strongly influenced the retention of the enzyme activity in the model films. The best results were obtained with a film matrix composed of 12% (w/v) acrylamide plus 0.6% (w/v) bisacrylamide. In this kind of film the retention of the enzyme activity was 59.0 +/- 5.4 (% +/- S.D.; n = 9). It was found that the biochemical and cytochemical (with TNBT) assay as applied to the model films both behave according to the Lambert-Beer law and that there was a high correlation between th biochemical and cytochemical data (r = 0.995)