IN-VITRO METABOLISM OF AN INSECT NEUROPEPTIDE BY NEURAL MEMBRANE PREPARATIONS FROM LYMANTRIA-DISPAR

Neural membrane fractions, prepared from brain-subesophageal ganglion complexes of the adult lepidopteran Lymantria dispar, contain at least two peptidases capable of metabolizing locust adipokinetic hormone-I in vitro. The initial fragments, pGlu(1)-Leu(2)-Asn(3) and Phe(4)-Thr( 5)-Pro(6)-Asn(7)-Trp(8)-Gly(9)-Thr(10) result from the action of an en dopeptidase with properties similar to those reported for neutral meta lloendopeptidase in Schistocerca gregaria and mammalian endopeptidase 24.11. The heptapeptide is further degraded by an aminopeptidase that exhibits kinetic properties similar to those described for aminopeptid ase 3.4.11.2. These enzymes appear to be responsible for the first two steps in AKH catabolism in L. dispar.