CHARACTERIZATION OF PROTEASE-RELEASING FACTORS ISOLATED FROM HEMOCYTES OF THE SOLITARY ASCIDIAN, HALOCYNTHIA-RORETZI

We have previously demonstrated that hemocytes of the solitary ascidia n Halocynthia roretzi respond to several stimuli, such as calcium iono phore, lipopolysaccharide (LPS) and phorbol 12-myristate 13-acetate (P MA), and to release metalloproteases. Here, we show that H. roretzi he mocytes contained two substances, named protease-releasing factors A a nd B, which induced the release of metalloproteases from the hemocytes . Factor A was isolated from the acid-ethanol extract of hemocytes by gel filtration, while factor B was isolated from the hypotonic extract of hemocytes by cation exchange chromatography. The former factor was a heat-labile, large molecule and the latter was a heat-stable, small molecule. We found that these factors existed only in some types of h emocytes.