SERINE-PROTEASE INHIBITOR ACTIVITY OF RECOMBINANT SQUAMOUS-CELL CARCINOMA ANTIGEN TOWARDS CHYMOTRYPSIN, AS DEMONSTRATED BY SODIUM DODECYL SULFATE-POLYACRYLAMIDE GEL-ELECTROPHORESIS

Squamous cell carcinoma (SCC) antigen was tested, by sodium dodecyl su lfate-polyacrylamide gel electrophoresis, for its ability to inhibit t he activity of serine proteases, i.e., trypsin, chymotrypsin and elast ase. We demonstrated that the serine protease inhibitor (serpin) of SC C antigen is specific for chymotrypsin. Preincubation of chymotrypsin with recombinant SCC antigen inhibited chymotryptic digestion of gelat in and ovalbumin through the formation of sodium dodecyl sulfate-stabl e complexes. These findings promote understanding of the biological fu nctions of SCC antigen as serpin in the stratification of the normal s quamous cells and in the malignant behavior of the tumor cells.