[Use of albuminous standards in the quantitative cytochemistry of dehydrogenases]

A method for preparing albuminous standards with various concentrations of NBT formazans is proposed. Using these standards, the molar extinction coefficients for half and fully reduced formazans of NBT in the region from 450 to 650 nm were calculated. Since the absorption curves of half and fully reduced NBT formazans are identical either in vitro in the standards or enzymatically in tissues, the extinction coefficients calculated on the basis of these standards may be used for densitometrical estimation of cellular dehydrogenase activity.