Purification and characterization of a galactose-specific agglutinin from the haemolymph of the larval stages of the insect Calliphora vomitoria.

A lectin was isolated from the haemolymph of the blowfly larva Calliphora vomitoria. It agglutinated a variety of mammalian erythrocytes with varying specificities and was strongly inhibited by D-galactose and fetuin. The activity was also sensitive to chelators of metal ions, heating above 50 degrees C and proteolytic digestion. SDS-PAGE identified a glycoprotein with an Mr of 32,000 under reducing and nonreducing conditions which resolved to a band at pH 5.4 using isoelectric focusing. Using FPLC gel filtration the activity was isolated in a fraction with an Mr of 130,000. It is suggested that the native form of the molecule is a noncovalently associated tetramer.