Properties of achetakinin binding sites on malpighian tubule membranes from the house cricket, Acheta domesticus.
A biologically active 125I-labeled analogue of AK-II (3'-hydroxyphenyl propionic-Gly-Gly-Gly-Phe-Ser-Pro-Trp-Gly-NH2) was used to investigate the properties of achetakinin binding sites on plasma membranes from Malpighian tubules of Acheta domesticus. With optimized conditions, binding was rapid, reversible, and specific, and saturation studies revealed a single class of binding sites with Kd 0.55 nM and Bmax 39.9 fmol/mg membrane protein. The affinities of achetakinins for binding sites on tubule membranes ranked AK-V > AK III > AK-II > AK-I > or = AK-IV, in general agreement with their potencies in functional assays. However, IC50 values were several orders of magnitude higher than corresponding values for EC50, which suggests a considerable receptor reserve.
Chung
J S
JS
Department of Biology, Birkbeck College, University of London, UK.
Wheeler
C H
CH
Goldsworthy
G J
GJ
Coast
G M
GM
D000595:Amino Acid Sequence; D000818:Animals; D002462:Cell Membrane / Q000737:chemistry; D005260:Female; D006135:Gryllidae / Q000737:chemistry* / Q000648:ultrastructure; D007301:Insect Hormones / Q000378:metabolism*; D007700:Kinetics; D008297:Male; D008317:Malpighian Tubules / Q000737:chemistry* / Q000648:ultrastructure; D008969:Molecular Sequence Data; D009479:Neuropeptides / Q000378:metabolism*; D011869:Radioligand Assay; D018013:Receptors, Neuropeptide / Q000032:analysis*; D013329:Structure-Activity Relationship
D007301:Insect Hormones; D009479:Neuropeptides; D018013:Receptors, Neuropeptide; C095262:achetakinin II; C095261:achetakinin receptor