Degradation of pheromone biosynthesis-activating neuropeptide (PBAN) by hemolymph enzymes of the tobacco hornworm, Manduca sexta, and the corn earworm, Helicoverpa zea.
The tritium-labeled bis-norleucine analog of Helicoverpa zea pheromone biosynthesis-activating neuropeptide ([3H]NLPBAN) was incubated in vitro with hemolymph from Manduca sexta or H. zea adult females. The incubations resulted in the formation of several tritium-labeled degradation products. At a [3H]NLPBAN concentration of 0.9 microM the degradation proceeded at a very slow but physiologically plausible rate (2-10 fmol/min/microliters hemolymph). The primary [3H]NLPBAN degradation reaction in M. sexta hemolymph was not inhibited by 20 microM leupeptin, 0.1 mM amastatin, 1 mM EDTA, 1 mM EGTA, 1 mM 1,10-phenanthroline, or 2 mM 4-(2-aminoethyl)benzenesulfonyl fluoride; but secondary reactions may have been affected, as some of the inhibitors changed the radio-HPLC profile of the degradation products. It is concluded that hemolymph of M. sexta and H. zea contains peptidase(s) capable of inactivating circulating PBAN.
Weirich
G F
GF
Insect Neurobiology and Hormone Laboratory, Agricultural Research Service, U.S. Department of Agriculture, Beltsville, Maryland 20705-2350, USA.
Kochansky
J P
JP
Masler
E P
EP
Lusby
W R
WR
Feldlaufer
M F
MF
Raina
A K
AK
Svoboda
J A
JA
D000595:Amino Acid Sequence; D000818:Animals; D010450:Endopeptidases / Q000378:metabolism*; D005260:Female; D006458:Hemolymph / Q000201:enzymology*; D018402:Manduca / Q000201:enzymology*; D008969:Molecular Sequence Data; D009036:Moths / Q000201:enzymology*; D009479:Neuropeptides / Q000378:metabolism*; D010675:Pheromones / Q000378:metabolism; D011480:Protease Inhibitors / Q000494:pharmacology
D009479:Neuropeptides; D010675:Pheromones; D011480:Protease Inhibitors; C079709:pheromone biosynthesis activating neuropeptide, Helicoverpa zea; D010450:Endopeptidases