Journal of Chemical Ecology, Vol. 12, No. 2, 1986 BINDING AND HYDROLYSIS OF RADIOLABELED PHEROMONE AND SEVERAL ANALOGS BY MALE-SPECIFIC ANTENNAL PROTEINS OF THE MOTH Antheraea polyphemus GLENN D. PRESTWICH, t'2 RICHARD G. VOGT, 3'4 and LYNN M. RIDDIFORD 3 ~-Department of Chemistry, State University of New York Stony Brook, New York 11794-3400 3Department of Zoology, University of Washington Seattle, Washington 98195 (Received March 18, 1985; accepted August 1, 1985) Abstract--Sensory hair proteins from antennae of males of the wild silk moth, Antheraea polyphemus (Lepidoptera, Saturniidae) were incubated with ra- diolabeled 6E, 11Z-hexadecadienyl acetate in the presence of unlabeled pher- omone analogs as competitive inhibitors. The two extracellular proteins of importance, a highly active sensillar esterase and an abundant 15,000 tool wt binding protein, interact to degrade labeled pheromone less efficiently in the presence of certain unsaturated acetate analogs of the natural pheromone. Enzymatic hydrolysis of the acetate (or diazoacetate) was also exam- ined for three pheromone analogs: [11,12-3H2]-6E,11Z-hexadecadienyl di- azoaeetate, [ll,12-3H2]-hexadecyl acetate, and [9,10-3Hz]-9Z-tetradecenyl acetate. The former two are poor substrates at concentrations over four orders of magnitude. The 9Z-14:Ac, however, is the best alternative substrate for this in vitro pheromone metabolism system. Unlabeled 9Z-14: Ac is also the best competitive inhibitor of the hydrolysis of labeled 6E,11Z-16:Ac. Whereas the tritiated natural pheromone shows a flat response (ca. 40% con- version) to increasing concentrations from 3 x 10 9 to 3 x 10 6 M, tritiated 9Z-14:Ac is degraded more rapidly at higher concentrations. Key Words--Antherea polyphemus, Lepidoptera, Saturniidae, wild silk moth, radiolabeled pheromone, pheromone binding, pheromone hydrolysis, anten- nal proteins. ~ Fellow of the Alfred P. Sloan Foundation (1981-1985) and Camille and Henry Dreyfus Teacher- Scholar (1981-1986). 4present address: Department of Chemistry, State University of New York, Stony Brook, New York, 11794. 323 0098-0331/86/0200-0323505.00/0 9 1986Plenum Publishing Corporation