Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.21.9 (enterokinase)
 675 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A novel form of gastric inhibitory polypeptide (GIP), later also referred to as glucose-dependent insulinotropic polypeptide, has been isolated from bovine upper intestine. The purification was monitored by a recently developed radioreceptor assay, specific for GIP, using membrane preparations from hamster beta-cell tumors. A combination of ion-exchange and reverse-phase high-performance liquid chromatography was used in the isolation which resulted in homogeneous bovine GIP. Bovine GIP is, like porcine GIP, composed of 42 amino acid residues. The sequence is: Tyr-Ala-Glu-Gly-Thr-Phe-Ile-Ser-Asp-Tyr-Ser-Ile-Ala-Met-Asp-Lys-Ile-Arg- Gln-Gln - Asp-Phe-Val-Asn-Trp-Leu-Leu-Ala-Gln-Lys-Gly-Lys-Lys-Ser-Asp-Trp-Ile-His- Asn-Ile - Thr-Gln, which differs from that of the previously characterized porcine GIP by having isoleucine instead of lysine at position 37. Upon proteolytic digestion of GIP with the staphylococcal V8 protease and with enterokinase, two fragments are formed in each case, corresponding to GIP1-3, GIP4-42, and GIP1-16, GIP17-42, respectively.
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PMID:A novel form of gastric inhibitory polypeptide (GIP) isolated from bovine intestine using a radioreceptor assay. Fragmentation with staphylococcal protease results in GIP1-3 and GIP4-42, fragmentation with enterokinase in GIP1-16 and GIP17-42. 639 23

Glucose-dependent insulinotropic polypeptide or gastric inhibitory polypeptide (GIP) is a 42 amino acid intestinal hormone, which exhibits several direct and indirect effects on fat and glucose metabolism. To determine the bioactive region(s) of the molecule, synthetic and proteolytic fragments of the hormone were generated and tested for their ability to induce a biological response in the isolated, perfused rat pancreas and stomach. A synthetic fragment corresponding to porcine GIP residues 1-30 retained strong insulinotropic activity in the isolated, perfused rat pancreas but greatly reduced somatostatinotropic activity in the isolated perfused rat stomach. A synthetic fragment corresponding to porcine GIP residues 15 to 30 was biologically inactive. However, enterokinase treatment of the synthetic 15-30 fragment restored partial insulinotropic activity in the isolated, perfused rat pancreas. The hypothesis that the restoration of biological activity was due to the enzymatic removal of the amino-terminal dipeptide (Asp-Lys) of GIP15-30 was supported by the observation that a synthetic fragment lacking these two residues was also insulinotropic. Further fractionation of the molecule generated a biologically active 19-30 fragment, suggesting that the residues necessary for the insulin response are contained within this region.
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PMID:The insulinotropic region of gastric inhibitory polypeptide; fragment analysis suggests the bioactive site lies between residues 19 and 30. 896 53