Modified Simple Colorimetry of Dehydrogenase Activity in Shellfishes using Tetrazolium Chloride

A simple colorimetry procedure for the determination of dehydrogenase activity in shellfishes was developed. In the previous paper, we reported a colorimetry of dehydrogenase activity in oyster gill. Triphenyltetrazolium chloride (TTC) is reduced to triphenylformazan (TF) by dehydrogenase in oyster gill. The dehydrogenase activity in shellfish muscle is considerably lower than in oyster gill, and could not readily be measured. Therefore, a study was done on the activation of dehydrogenase.When phosphate buffer (pH 7.4) was added to sodium chloride-TTC reagent (0.2% TTC-0.1% sodium succinate-3% sodium chloride), dehydrogenase activity in shellfish muscle was markedly increased. The dehydrogenase activity was also influenced by pH, osmotic pressure and others.The composition of TTC reagent was 0.2% TTC-0.1% sodium succinate-2.84% disodium hydrogen phosphate-2.34% sodium chloride. A sample of shellfish muscle was sliced at about 1.5mm thickness, soaked in TTC reagent, incubated at 37° for 30min, and treated by the same procedure as in the case of oyster gill. Thus, dehydrogenase activity was activated sufficiently to be measured.It was also possible to determine dehydrogenase activity in oyster gill using this TTC reagent.