Possible involvement of lumichrome in the binding of storage protein to its receptor in Sarcophaga peregrina.

Previously, a receptor molecule on the surface of fat body cells of Sarcophaga peregrina larvae that is involved in the uptake of storage protein from the hemolymph was shown to be a 120-kDa protein (Ueno, K., and Natori, S. (1984) J. Biol. Chem. 259, 12107-12111). This paper reports evidence that lumichrome (7,8-dimethylalloxazine) may be present in the binding site of the receptor and mediate the binding of storage protein and receptor. A stoichiometric amount of lumichrome was shown to bind to the storage protein under conditions in which the latter bound to its receptor.