Detection of endogenous peroxidase and phenoloxidase in the mantle and liver of the clam Ruditapes philippinarum

Dongwu Liu1,2, Ling Kong1 and

Abstract

Peroxidase catalyzes the oxidation of a large variety of hydrogen-donating substrates in the presence of hydrogen peroxide, while phenoloxidase (PO) catalyzes mono- and/or diphenols into quinines and melanin with oxygen as a proton acceptor. Oxidases reduce the molecular oxygen during oxidation of their substrates, and further yield the oxidized product hydrogen peroxide. In this study, the distribution of endogenous peroxidase and PO in the mantle and liver of the Clam Ruditapes philippinarum were investigated with diaminobenzidine (DAB) and L-Dopa method, respectively. The results indicated that peroxidase and PO distributed widely in the mantle and liver cells of Ruditapes philippinarum. The peroxidase and PO reactivity were detected in many epithelial cells of the gill. However, peroxidase and PO were mainly present at the edges of mantle. There were fewer granules of peroxidase and PO in the interior of the mantle. It shows that peroxidase and PO may play an important role in regulating the defence system in the mantle and liver of the Clam Ruditapes philippinarum.