Binding of juvenile hormone III to lipophorin from the american cockroach Periplaneta americana

Abstract

Whole hemolymph from the American cockroach, Periplaneta americana, efficiently binds juvenile hormone (JH) Ill and to a lesser extent JH-I and 10,llepoxyfarnesyl diazoacetate (EFDA). The dissociation constants for racemic JH-Ill and EFDA are 30 2 2 n M and 1.0 pM, respectively. Isolated lipophorin also binds [3H]jH-lll and to a lesser extent JH-I. Other proteins from the hemolymph do not bind JH-Ill. Binding of JH-Ill to lipophorin i s enantioselective. The dissociation constant, measured with a92% 10Rand 8% 10s mixture, is21 t 2 nM. Each lipophorin molecule contains one specific binding site for JH-Ill. It i s concluded that lipophorin i s the JH-Ill-specific transport protein in the hemolymph of the American cockroach. By a combination of photoaffinity labelling and gradient electrophoresis with sodium dodecyl sulphate o n polyacrylamide gel, we showed that the JH-Ill-specific binding site is probably located o n apolipophorin I.

Regulation of JH titers: The relevance of degradative enzymes and binding proteins

“…It is also enantioselective, because the protein exhibits much higher affinity for the natural (10R)-JHIII than for the unnatural (10s)-enantiomer. Each lipophorin molecule contains one JHIII-specific binding site, which is located on apolipophorin I (Rayne and Koeppe, 1988;de Kort and Koopmanschap, 1989;Okot-Kotber and Prestwich, 1991). Lipophorin was subsequently shown to be the JHBP in other insect species representing several orders: Dyctyoptera; Isoptera, and probably also in Hymenoptera and Diptera (de Kort et al, 1984;van Mellaert et al, 1985;Rayne and Koeppe, 1988;Shemshedini and Wilson, 1988;Okot-Kotber and Prestwich, 1991;King and Tobe, 1992;Lanzrein et al, 1993;Trowel1 et al, 1995).…”

Carotenoid transport by the larval lipophorin of the southwestern corn borer, Diatraea grandiosella

“…In general, a large bathochromatic shift in the absorption spectrum characterizes true carotenoproteins which have carotenoids associated with proteins in stoichio- metric amounts through noncovalent linkages (Goodwin, 1984). By contrast, a stoichiometric relationship exists between the lipophorin of the American cockroach, Periplaneta americana, and juvenile hormone-III because a specific binding site is present for this hormone, probably on apolipophorin-I (de Kort & Koopmanschap, 1989). A direct relationship was found to exist between the amount of dietary 0~-carotene and that associated with lipophorin (Table 1).…”

Juvenile hormone binding proteins of termites detected by photoaffinity labeling: Comparison of Zootermopsis nevadensis with two rhinotermitids

“…Some JHBPs are lipophorins, that is, lipoproteins w ich also apparently shuttle lipids in insect hemolymph [34]. Those lipophorins have been isolated and characterized from Leptinofarsa decemlineutu [19], Periplunetu umericuna [19,35], and Leucophaeu maderue [36]. It appears likely that the JHBP in Z .…”