GLYCOSYLATION AND ADHESIVENESS DIFFERENTIATE LARVAL CERATITIS-CAPITATA TYROSINASES

Larval Ceratitis capitata phenoloxidases (POs) from hemocytes, serum, integument, and fat body were analyzed. Two types of PO were recorded:the tyrosinase type found in hemocytes, serum, integument, and fat body and the laccase type found in integument. Tyrosinase from all larval tissues and integumental laccase as well, showed similarity in molecular weight (93 KDa), activation by Escherichia coli al 5 mM Ca2+, and reactivity to antibodies raised against serum tyrosinase. However, the enzymes differed with respect to their glycosylation and adhesiveness. The serum and integumental enzyme forms contain concanavalin A reacting material, whereas hemocyte and integumental tyrosinase(si are adhesive. These differences in enzyme forms, although not influencing their substrate specificity, seem to give advantages to performing their function, i.e., the adhesive enzyme form facilitates the adherence to E. coli cell wall and hemocyte surface (unpublished data) while the glycosylated form facilitated the secretion into serum. (C) 1994 Wiley-Liss, Inc.