Binding of gastrin to gastric transferrin

Abstract

Binding of iz51-gastrin2,i7 to porcine gastric transferrin has been demonstrated by covalent cross-linking with disuccinimidyl suberate. The concentration of gastrini, required to reduce cross-linking by 50% was approx. 100 PM. The occurrence of both gastrin and gastric transferrin in porcine gastric mucosa and lumen suggests a novel synergistic role for the observed interaction in the uptake of dietary iron. Gastrin Iron uptake Transferrin

Binding of progastrin fragments to the 78 kDa gastrin‐binding protein

“…The 78 kDa GBP was partially purified from detergent extracts of porcine gastric mucosal membranes by lectin and ion-exchange chromatography [9,10]. The following protease inhibitors were included in all buffers to prevent proteolysis: pepstatin 1 /2M, benzamidine 1 mM, hexamethylphosphoramide 0.1% (w/v), aprotinin 500 units/ml.…”

“…The following protease inhibitors were included in all buffers to prevent proteolysis: pepstatin 1 /2M, benzamidine 1 mM, hexamethylphosphoramide 0.1% (w/v), aprotinin 500 units/ml. Crosslinking of [~:5I]Nle~5-gastrin2 ~7 to the GBP with disuccinimidylsuberate was measured as described previously [9] in the presence of increasing concentrations of gastrin analogues. The products of the cross-linking reaction were separated by polyacrylamide gel electrophoresis, and radioactivity associated with the 78 kDa GBP was detected and quantitated with a phosphorimager (Molecular Dynamics, Sunnyvale, CA).…”

“…The gastrin/CCK-C receptor, which is the target for the inhibitory effects of gastrin/CCK receptor antagonists on colon carcinoma cell proliferation [5], is identical to a 78 kDa gastrinbinding protein (GBP) [8]. The GBP, which has been purified from porcine gastric mucosal membranes [9,10], is a member of the family of fatty acid oxidation enzymes possessing enoyl CoA hydratase and 3-hydroxyacyl CoA dehydrogenase activities [11].…”

Binding of a valproate metabolite to the trifunctional protein of fatty acid oxidation

“…The 78 kDa ~-subunit catalyses the hydration of enoyl-CoA and the dehydrogenation of 3-hydroxyacyl-CoA, and the 48-51 kDa 13-subunit catalyses the cleavage of acetyl-CoA from the resultant 3-ketoacyl-CoA [6]. Binding of the peptide hormone gastrin to the a-subunit of the TP, with an IC50 value of 200 nM, has been demonstrated by covalent crosslinking [7,8]. Gastrin occupies both the hydratase and dehydrogenase active sites of TPct, since substrates of the enoylCoA hydratase activity, and products of the 3-hydroxyacylCoA dehydrogenase activity, both compete for gastrin binding [8].…”

The β‐subunit of the gastric H+/K+‐ATPase can occur without the α‐subunit

“…The @-subunit itself was not detected by Coomassie blue staining, presumably because of its extensive glycosylation. The 78 kDa protein detected in the DEAE-Sepharose fractions has previously been shown to bind gastrin, and is a candidate for the gastric parietal cell gastrin receptor [19].…”