A fluorometric micromethod for estimation of carnosinase in dried blood samples

We describe a microfluorometric method for determination of carnosinase activity in dried blood spots on filter paper. The carnosinase in discs punched from such dried blood specimens is activated with cadmium at 30 degrees C. After incubation with the substrate carnosine at the same temperature, histidine is determined fluorometrically. We compare the results of this method with those of a fluorometric method using liquid blood and assess the stability of the enzyme in dried blood on filter paper. The presence of erythrocytes has no effect on the activity. The method may be useful in early detection of carnosinase deficiency and certain other metabolic disorders.