Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: DrugBank:EXPT00572 (Asn)
 11,732 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Thirteen neuropeptides varying in length from 7 to 11 residues and ending C-terminally in -Phe-Met-Arg-Phe-NH2 (calliFMRFamides 1-13) and one dodecapeptide ending in -Met-Ile-Arg-Phe-NH2 (calliMIRFamide 1) have been isolated from thoracic ganglia of the blowfly Calliphora vomitoria. Different repeating patterns of amino acid sequences enable the peptides to be arranged into distinct groups. One such group of five nonapeptides has the sequence Xaa-Pro-Xaa-Gln-Asp-Phe-Met-Arg-Phe-NH2. Three peptides in this group, with the N-terminal tripeptide sequences Thr-Pro-Gln-, Thr-Pro-Ser-, and Ser-Pro-Ser-, are able to induce fluid secretion from the isolated salivary gland of Calliphora at a concentration of 0.1 to 1 nM. However, two other members of this group with the N-terminal tripeptide sequences Lys-Pro-Asn- and Ala-Pro-Gly-, the latter being the most abundant peptide isolated, were inactive in this assay, as were all the other peptides isolated. This indicates that the N terminus (in addition to the C terminus as previously found for FMRFamides of other organisms) is crucial for at least some biological activities.
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PMID:Isolation, structure, and activity of -Phe-Met-Arg-Phe-NH2 neuropeptides (designated calliFMRFamides) from the blowfly Calliphora vomitoria. 154 95

A series of di- and tripeptides containing aspartic or asparagine as N-terminal or intermediate amino acid were synthesized and tested for their effect on human platelet aggregation in vitro. It was found that only Met-Asp(or Asn)-Phe-NH2 inhibited platelet aggregation induced by collagen, ADP or adrenaline. Asn-Phe-NH2 and to a small extent Asp-Phe-NH2 presented strong aggregatory activity at low concentrations (at 0.5 mM or lower than this). All the other peptides tested, did not show any effect on platelet aggregation even at the concentration of 10 mM.
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PMID:Effect of X-Asp (or Asn)-Phe-Nh2 (where X; H, Met) peptides on human platelet aggregation in vitro. 155 37

An oxytocin/vasopressin-immunoreactive peptide was isolated from nerve terminals of the 'neurosecretory system of the vena cava' in octopus. It was purified by HPLC combined with a RIA for oxytocin. Characterization of the peptide by automated Edman degradation, plasma desorption mass spectroscopy, enzymatic treatment and coelution experiments resulted in the structure: Cys-Tyr-Phe-Arg-Asn-Cys-Pro-Ile-Gly-NH2, a nonapeptide with a molecular weight of 1070 Da and a 1-6 disulfide bond. This cephalopod neuropeptide, here called 'cephalotocin', exhibits 78% sequence homology with the vertebrate neurohypophysial hormone mesotocin and clearly belongs to the oxytocin/vasopressin family of vertebrates, confirming the high conservation of this peptide family.
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PMID:A new peptide of the oxytocin/vasopressin family isolated from nerves of the cephalopod Octopus vulgaris. 158 45

Adipokinetic hormones AKH I (pGlu-Leu-Asn-Phe-Thr-Pro-Asn-Trp-Gly-Thr-NH2) and AKH II (pGlu-Leu-Asn-Phe-Ser-Trp-Gly-Thr-NH2) are synthesized by neurosecretory cells (NSC) of the corpora cardiaca (CC) in the locust, Schistocerca gregaria. These NSC constitute a homogeneous 'peptide factory' as each cell synthesizes both AKH I and AKH II. This homogeneity makes the CC an excellent system in which to study aspects of neuropeptide biosynthesis. This report summarizes recent findings on AKH inactivation and metabolism, as well as on AKH prohormone processing and biosynthesis.
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PMID:Adipokinetic hormones: cell and molecular biology. 160 Nov 7

The conserved Asn 229 of thymidylate synthase (TS) forms a cyclic hydrogen bond network with the 3-NH and 4-O of the nucleotide substrate dUMP. The Asn 229 to Asp mutant of Lactobacillus casei thymidylate synthase (TS N229D) has been prepared, purified, and investigated. Steady-state kinetic parameters of TS N229D show 3.5- and 10-fold increases in the Km values of CH2H4folate and dUMP, respectively, and a 1000-fold decrease in kcat. Most important, the Asp 229 mutation changes the substrate specificity of TS to an enzyme which recognizes and methylates dCMP in preference to dUMP. With TS N229D the Km for dCMP is bout 3-fold higher than for dUMP, and the Km for CH2H4folate is increased about 5-fold; however, the kcat for dCMP methylation is 120-fold higher than that for dUMP methylation. Specificity for dCMP versus dUMP, as measured by kcat/Km, changes from negligible with wild-type TS to about a 40-fold increase with TS N229D. TS N229D reacts with CH2H4folate and FdUMP or FdCMP to form ternary complexes which are analogous to the TS-FdUMP-CH2H4folate complex. From what is known of the mechanism and structure of TS, the dramatic change in substrate specificity of TS N229D is proposed to involve a hydrogen bond network between Asp 229 and the 3-N and 4-NH2 of the cytosine heterocycle, causing protonation of the 3-N and stabilization of a reactive imino tautomer. A similar mechanism is proposed for related enzymes which catalyze one-carbon transfers to cytosine heterocycles.
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PMID:Mutation of asparagine 229 to aspartate in thymidylate synthase converts the enzyme to a deoxycytidylate methylase. 160 34

The caudal portion of the spinal cord of elasmobranch fish incorporates a diffuse neuroendocrine system. Using an antiserum raised against urotensin II from a teleost fish (goby) to facilitate purification, a peptide structurally related to urotensin II was isolated in pure form from an extract of neuroendocrine tissue from the spinal cord of the European common dogfish, Scyliorhinus canicula. The primary structure of the peptide was established as: Asn-Asn-Phe-Ser-Asp-Cys-Phe-Trp-Lys-Tyr-Cys-Val. The amino acid sequence was confirmed by chemical synthesis. A comparison of this sequence with those of the known teleost urotensin II peptides shows that the cyclic region of the molecule has been fully conserved between species and suggests that the presence of an acidic residue at position 5 and a hydrophobic residue at position 12 are important features for the biological activity of the peptide. The dogfish spinal cord extract also contained a high concentration of the calcium-binding protein, parvalbumin and the amino acid sequence at its NH2 terminus [residues (1-50)] was determined.
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PMID:Purification and characterization of urotensin II and parvalbumin from an elasmobranch fish, Scyliorhinus canicula (common dogfish). 162 Feb 90

A peptide belonging to the pancreatic polypeptide (PP) family was isolated in pure form from the intestine of the European green frog (Rana ridibunda). The primary structure of the peptide was established as: Tyr-Pro-Pro-Lys-Pro-Glu-Asn-Pro-Gly-Glu10-Asp-Ala- Ser-Pro-Glu-Glu-Met-Thr-Lys-Tyr20-Leu-Thr-Ala-Leu-Arg-His-Tyr-Ile- Asn-Leu30-Val - Thr-Arg-Gln-Arg-Tyr-NH2. This amino acid sequence shows moderate structural similarity to human PYY (75% identity) but stronger similarity to the PP family peptides isolated from the pancreas of the salmon (86%) and dogfish (83%). The data suggest that the two putative duplications of an ancestral PP family gene that have given rise to PP, PYY and NPY in mammals had already taken place by the time of the appearance of the amphibia. In fish, however, only a single duplication has occurred, giving rise to NPY in nervous tissue and a PYY-related peptide in both pancreas and gut.
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PMID:Primary structure of frog PYY: implications for the molecular evolution of the pancreatic polypeptide family. 162 Jun 52

A method for the preparation of a biotinylated resin that can be elongated by standard methods of solid-phase peptide synthesis to give peptides biotinylated at the carboxy terminus is described. This methodology is particularly important for the preparation of biotinylated peptides in which a free amino terminus is required. Coupling of N epsilon-9-fluorenylmethoxycarbonyl-(Fmoc)-N alpha-tert-butyloxycarbonyl(Boc)-L- lysine to p-methylbenzhydrylamine resin, followed by removal of the Fmoc protecting group and reaction with (+)-biotin-4-nitrophenyl ester yielded N alpha-Boc-biocytin-p-methyl-benzhydrylamine resin. The utility of this resin was tested by the synthesis of a biotinylated peptide, Gly-Asn-Ala-Ala-Ala-Ala-Arg-Arg-biocytin-NH2, for use as an in vitro substrate for myristoyl-CoA:protein N-myristoyltransferase (NMT), the enzyme that catalyzes protein N-myristoylation. Analysis of the peptide derivative by HPLC and mass spectrometry revealed a single major product of the expected mass, indicating that the biotin group survived cleavage and deprotection with HF. The biotinylated peptide served as a substrate for NMT, and the resulting myristoylated peptide could be quantitatively recovered by adsorption to immobilized avidin.
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PMID:A general method for preparation of peptides biotinylated at the carboxy terminus. 162 86

We examined the effects of arginine-vasopressin (AVP) C-terminal fragment 4-9, which facilitates learning and memory, on the extracellular acetylcholine (ACh) release in hippocampus of freely-moving rats using the microdialysis technique. Following administration of AVP4-9, p-Glu-Asn-Cys[Cys]-Pro-Arg-Gly-NH2, through the dialysis probe into the hippocampus, ACh levels in dialysates from the hippocampus increased markedly in dose and time dependent manner at 2-2.5 and 2.5-3 hr. AVP1-9, the parent peptide, has a similar enhancing effect on ACh release as AVP4-9. Stimulated ACh release by AVP4-9 was significantly inhibited by V1-selective receptor antagonist ([1-(beta-mercapto-beta,beta-cyclopentamethylenepropionic acid), 2-(O-methyl)-tyrosine]AVP), but not by V2-selective antagonist ([1-(beta-mercapto-beta,beta-cyclopentamethylenepropionic acid), 2-D-Ile, 4-Ile]AVP). From these observations, it is demonstrated that AVP4-9 stimulates the ACh release in rat hippocampus via mediating V1-like vasopressin receptors.
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PMID:Arginine-vasopressin fragment 4-9 stimulates the acetylcholine release in hippocampus of freely-moving rats. 162 20

Human furin is a calcium-dependent serine endoprotease that can efficiently cleave many precursor proteins on the carboxyl side of the consensus cleavage sequence, -Arg-X-Lys/Arg-Arg-, both in vivo and in vitro. Analysis of furin proteins in extracts of cells infected with a vaccinia recombinant expressing human furin show that the enzyme is present as two prominent forms of 90 and 96 kDa. Because the structurally related bacterial subtilisins require endoproteolytic removal of the NH2-terminal pro-region by an autocatalytic intramolecular cleavage, we speculated that the size heterogeneity in the furin doublet similarly may result from a proteolytic removal of an NH2-terminal pro-region. Here we report identification of the 90-kDa furin NH2 terminus and, based on the reported sequence of the furin cDNA, demonstrate that this furin protein is derived from a larger precursor by an endoproteolytic cleavage on the COOH-terminal side of a consensus furin cleavage site, -Arg-Thr-Lys-Arg107-. Expression of mutant furin molecules containing an altered cleavage site (Arg104----Ala or Arg107----Gly) resulted in the production of only the 96-kDa furin protein. Assays of furin-dependent cleavage of a protein substrate in vitro showed that proteolytic activity was associated with the 90-kDa and not the 96-kDa furin protein, demonstrating that removal of the NH2-terminal pro-region is required for furin activity. Expression of a third furin construct containing a mutation of the active site aspartate (Asp153----Asn) similarly resulted in the expression of only the 96-kDa protein, suggesting that furin activation occurs by an autoproteolytic cleavage. Finally, the production of 90-kDa furin from either site-directed furin mutant could not be potentiated by overexpressing active furin, suggesting that the autoproteolytic activation was an intramolecular event.
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PMID:Activation of human furin precursor processing endoprotease occurs by an intramolecular autoproteolytic cleavage. 162 22


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