Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P01350 (gastrin)
 9,683 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The precursor of the acid-stimulating hormone gastrin contains a phosphorylation site which is immediately adjacent to a functionally important cleavage site, and which occurs in a sequence resembling the phosphorylation sites in casein. We have examined phosphorylation of human preprogastrin 93-101 with [gamma-32P]ATP by a Triton-solubilized Golgi membrane preparation from mammary glands of lactating rats. The activity of solubilized Golgi membranes was approx. an order of magnitude greater than that of intact vesicles suggesting a luminal orientation of the kinase. Incorporation of 32P was linear for up to 12 min at 30 degrees C, and the half-maximal rate of phosphorylation at 1 mM ATP was observed at peptide concentrations of 0.2 mM. The Km for ATP was 0.12 mM and the maximal velocity was 2.17 nmol of peptide per min per mg Golgi protein. Proteinase inhibitors (leupeptin, pepstatin, benzamidine) and p-nitrophenyl phosphate did not influence phosphorylation. The incorporation of 32P was inhibited by poly-L-lysine but not by heparin. We conclude that the phosphorylation site in progastrin is a substrate for a Golgi membrane kinase and that a similar enzyme might act on endogenous progastrin in vivo.
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PMID:Phosphorylation of human preprogastrin 93-101 by a Golgi membrane kinase from rat mammary gland. 814 83

[(125)I]Gastrin releasing peptide (GRP) and [(125)I]somatostatin were cross-linked with bis(sulfosuccinimidyl)suberate to a 120 kDa membrane protein in Triton extracts of different cell types. Labeling of the 120 kDa protein was blocked (IC(50) ? 10(?8) M) by unlabeled GRP, GRP(14-27) and somatostatin but not by 100 nM bombesin, [Tyr(4)]bombesin, AcGRP(20-27), three biologically active somatostatin analogs or peptides unrelated to GRP or somatostatin. Binding involves a tripeptide sequence consisting of aryl, nonpolar and positively charged moieties in residues 7-9 (Phe-Trp-Lys) of the receptor binding site of somatostatin and residues 15-17 (Tyr-Pro-Arg) of GRP, a region distinct from its biologically active carboxyl-terminus.
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PMID:Somatostatin competes with the central portion of gastrin releasing peptide for binding to a 120 kDa protein. 2050 92