Identification of a gastrin binding protein in porcine gastric mucosal membranes by covalent cross-linking with iodinated gastrin

Journal Article · Mon Sep 15 04:00:00 EDT 1986 · J. Biol. Chem.; (United States)

OSTI ID:5073446

Baldwin, G S; Chandler, R; Scanlon, D B; Weinstock, J

A gastrin binding protein (GBP) has been identified in detergent extracts of porcine gastric mucosal membranes by covalent cross-linking to /sup 125/I-(Nle15)gastrin with disuccinimidyl suberate. The apparent molecular weight of the cross-linked complex (80,000) is uneffected by reduction suggesting that the GBP is not composed of disulfide-bonded subunits. Subtraction of the molecular weight of 125I-gastrin indicates that the molecular weight of the GBP is 78,000. A similar molecular weight has been observed previously for the gastrin receptor (74,000) on intact canine parietal cells and plasma membranes therefrom, and for the receptor for the related hormone cholecystokinin (76,000-85,000) on pancreatic acinar membranes under reducing conditions. The similarity in molecular weight between the gastrin receptor and the solubilized GBP suggests that the latter protein is probably the gastrin receptor. However, the concentration (2 microM) of (Nle15)gastrin required for 50% inhibition of cross-linking of gastrin to the GBP solubilized in 0.1% Triton X-100 is 200-fold greater than the value (10 nM) observed for the gastrin receptor on isolated canine gastric parietal cells. A lower concentration (0.3 microM) of (Nle15)gastrin was required to inhibit cross-linking in a milder detergent (0.4% digitonin, 0.08% cholate). Thus, the reduced affinity for gastrin of the putative solubilized form of the gastrin receptor appears to be a result of detergent extraction.

• Research Organization: Ludwig Institute for Cancer Research, Victoria, Australia
• OSTI ID: 5073446
• Journal Information: J. Biol. Chem.; (United States), Journal Name: J. Biol. Chem.; (United States) Vol. 26; ISSN JBCHA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ANIMALS
BETA DECAY RADIOISOTOPES
BODY
CELL CONSTITUENTS
CELL MEMBRANES
DAYS LIVING RADIOISOTOPES
DIGESTIVE SYSTEM
DOGS
DOMESTIC ANIMALS
ELECTRON CAPTURE RADIOISOTOPES
ELEMENTS
GASTRIN
GASTROINTESTINAL TRACT
GUINEA PIGS
HORMONES
INTERMEDIATE MASS NUCLEI
IODINE 125
IODINE ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
LABELLED COMPOUNDS
MAMMALS
MEMBRANES
METALS
MOLECULAR WEIGHT
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
ORGANS
PEPTIDE HORMONES
PEPTIDES
POLYPEPTIDES
PROTEINS
RABBITS
RADIOISOTOPES
RADIORECEPTOR ASSAY
RATS
RODENTS
STOMACH
SWINE
TRACER TECHNIQUES
VERTEBRATES