Presence of phenoloxidase and prophenoloxidase in the epidermal cells and the epidermis mucus of the lancelet Branchiostoma belcheri tsingtauense

The enzyme phenoloxidase (PO) has been shown to be present in both inverteb rates and vertebrates, yet little is known about the PO in Branchiostoma be lcheri tsingtauense, the lancelet or amphioxus, a cephalochordate transitio nal from invertebrates to vertebrates. It was shown in the present study th at the PO activity existed not only in the epidermal cells of the animal bu t also in its epidermis mucus. The enzyme is present in the mucus and the e pidermal cells predominantly as an inactive precursor, prophenoloxidase (pr oPO). This is the first report on the presence of the PO activity in the mu cus of not only lancelets but also marine animals. The PO enzyme could serv e as protecting agents against environmental pathogens and foreign bodies.