USE OF CONCANAVALIN-A IN THE PURIFICATION OF JUVENILE-HORMONE ESTERASE FROM THE HEMOLYMPH AND THE FAT-BODY OF LYMANTRIA-DISPAR

A new method for the purification of juvenile hormone esterase (JHE) exploits the ability of Sepharose-coupled concanavalin A to bind to glycoproteins. Preparation of homogenous esterase from the plasma of the gypsy moth, Lymantria dispar, was accomplished by a procedure employing polyethylene glycol (PEG) precipitation, Superose-12 gel filtration, concanavalin A-Sepharose affinity chromatography and mono-Q FPLC. The 62 kDa plasma glycoprotein was purified 1325-fold by the four-step procedure with an 8% recovery of the original activity. A specific activity of 2650 nmol of juvenile hormone III (JH III) hydrolyzed per min per mg of protein at 28-degrees-C was determined for the purified enzyme. Concanavalin A-Sepharose chromatography also was used in the partial purification of JHE from the last stadium fat body of gypsy moth larvae. After precipitation with ammonium sulfate, the fat body enzyme was purified 239-fold by a single step using concanavalin A-Sepharose chromatography. Western blots showed that the fat body enzyme was similar in size to JHE purified from the plasma. These results are consistent with JHE being a glycoprotein.