Solubilization and Molecular Characterization of Active Pancreastatin Receptors from Rat Liver Membranes

V. Sanchez-Margalet
1997 Endocrinology  
Pancreastatin receptors were solubilized from rat liver membranes with the nonionic detergent Triton X-100. Binding of a iodinated analog of rat pancreastatin ([ 125 I-Tyr 0 ]pancreastatin) to the soluble fraction was time dependent, saturable, and reversible. Scatchard analysis of binding under equilibrium conditions indicated that the soluble extracts contained a single class of pancreastatin-binding sites, with a binding capacity of 14 fmol/mg protein and a K d of 0.3 nM. As observed with
more » ... brane-bound receptors, binding of [ 125 I]pancreastatin to soluble extracts was inhibited by guanine nucleotides with the following rank order of potency: guanyl-5Ј-yl-imidodiphosphate Ͼ GTP Ͼ GDP Ͼ GMP, indicating that the soluble receptors are functionally linked to G proteins. Molecular analysis of the soluble pancreastatin receptor by covalent cross-linking to [ 125 I]pancreastatin using disuccinimidyl suberate and further identification on SDS-
doi:10.1210/en.138.4.1712 pmid:9075735 fatcat:ucab2usyabfadir25x5lrluqre