Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P20366 (substance P)
 21,176 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Binding of [3H]substance P (SP) and histamine release were examined using a cloned mouse mast cell line. SP binding was saturable and specific. In the presence of 30 mM Na2SO4/50 mM Tris buffer, SP interacted with two types of binding sites with Kd values of 0.3 and 40 nM. High-affinity SP binding was blocked by the inclusion of 0.5 uM of the NK1 receptor selective ligand septide in the binding mixture. Neurokinin A (NKA) evoked concentration-dependent histamine release. At concentrations in the nanomolar range, the NK1 preferring agonists SP, SP methylester and physalaemin evoked less than or equal to 5% net release of histamine, which was substantially less than the maximum effect of NKA (+37%) in the micromolar range. Pretreatment of the cells with the NK2 antagonist peptide A reduced NKA-induced histamine release. [D-Arg1,D-Phe5,D-Trp7,9,Leu11]-substance P, a putative SP antagonist, also elicited histamine release in the micromolar range, apparently acting as an agonist at the NK2 site. Compound 48/80, N-terminal SP fragments, neurokinin B and the two selective NK2 receptor antagonists cyclo(Gln-Trp-Phe-(R)-[ANC-2]Leu-Met) (peptide A) and cyclo(Gln-Trp-Phe-Gly-Leu-Met) (peptide B) were ineffective. Although the results suggest the coexistence of functional NK1 and NK2 receptors, it appears that in this mast cell line neurokinin-induced histamine release is primarily mediated by the NK2 receptor, characterized biochemically as a low affinity binding site with a Kd value of 40 nM for SP.
 ...
PMID:Evidence of NK1 and NK2 tachykinin receptors and their involvement in histamine release in a murine mast cell line. 137 67

This study describes the synthesis and effects of the first antagonist to the widely distributed neuropeptide, galanin, which inhibits the secretion of insulin. The first galanin antagonist is a 20-amino acid-long chimeric peptide of the composition galanin-(1-12)-Pro-substance P-(5-11) amide: Gly-Trp-Thr-Leu-Asn-Ser-Ala-Gly-Tyr-Leu-Leu-Gly-Pro-Gln-Gln-Phe-Phe-Gly- Leu-Met amide. The peptide dose dependently (IC50 = 1.0 nM) antagonizes the galanin-mediated inhibition of the glucose-induced insulin secretion from mouse pancreatic islets. The antagonist was also found to displace 125I-monoiodo-[Tyr26]galanin from membranes of the insulin producing Rin m 5F cells with an IC50 value of less than 0.1 nM. The antagonist is named galantide.
 ...
PMID:The novel high-affinity antagonist, galantide, blocks the galanin-mediated inhibition of glucose-induced insulin secretion. 137 72

Neutral endopeptidase 24.11 contains an active site arginine believed to function in substrate binding. This arginine is thought to form an ionic interaction with the COOH-terminal carboxylate of NEP substrates. The functionality of arginine 102 has been investigated by using site-directed mutagenesis to produce mutants in which this residue was converted to a lysine, glycine, glutamine, or glutamate. All of the mutants exhibited essentially full activity as determined with a synthetic peptide amide, glutaryl-Ala-Ala-Phe-4-methoxy-2-naphthylamide. In contrast, activity was detected only with the wild-type enzyme and the lysine mutant using a synthetic substrate containing a free COOH-terminal carboxylate, dansyl-Gly-Trp-Gly. Inhibition studies with the physiologically active peptide substrates substance P, endothelin, and angiotensin I, as well as substance P free acid, [D-Ala2,Leu5]enkephalin, and [D-Ala2,Leu5]enkephalinamide indicated a lack of importance of arginine 102 in substrate binding. With [D-Ala2,Met5]enkephalin and the chemotactic peptide, N-formyl-Met-Leu-Phe, a significant decrease in affinity is observed with the arginine 102 mutants. These results suggest that the contribution of arginine 102 to substrate binding is dependent upon the strength of other subsite interactions. Examination of dipeptides as inhibitors indicates that the nature and orientation of the P'2 residue is important in determining the strength of the interaction of arginine 102 with its substrates.
 ...
PMID:Analysis of the importance of arginine 102 in neutral endopeptidase (enkephalinase) catalysis. 137 21

An extract of the brain of the rainbow trout, Oncorhynchus mykiss contained high concentrations of both neurokinin A-like immunoreactivity (corresponding to 90 pmol mammalian neurokinin A/g wet tissue) and substance-P-like immunoreactivity (corresponding to 50 pmol mammalian substance P/g wet tissue) measured by radioimmunoassay using antisera directed against the C-terminal regions of the mammalian peptides. In contrast, an extract of the Atlantic cod. Gadus morhua contained only neurokinin-A-like immunoreactivity (151 pmol/g). This apparent paradox was resolved by determination of the primary structures of the fish tachykinins. Trout substance P (Lys-Pro-Arg-Pro-His-Gln-Phe-Phe-Gly-Leu-MetNH2) has the same amino acid sequence in its C-terminal region as that in the corresponding region of mammalian substance P. Cod substance P (Lys-Pro-Arg-Pro-Gln-Gln-Phe-Ile-Gly-Leu-MetNH2), however, contains a substitution at position 8 (Phe----Ile) that abolishes reactivity with the antiserum to substance P but permits reactivity with the antiserum to neurokinin A. The amino acid sequence of cod and trout neurokinin A is the same (His-Lys-Ile-Asn-Ser-Phe-Val-Gly-Leu-MetNH2) and shows two substitutions (Thr3----Ile and Asp4----Asn) compared with mammalian neurokinin A. The data indicate that nervous tissue of teleost fish contain tachykinins that are analogous to the peptides found in mammalian tissues.
 ...
PMID:Substance-P-related and neurokinin-A-related peptides from the brain of the cod and trout. 137 87

The nature of the interaction between spinally administered opioid and alpha-2 agonists was investigated using the substance P behavioral test in mice. Morphine and agonists which more selectively activate mu or delta opioid receptors were co-administered intrathecally with direct and indirect acting adrenergic agonists norepinephrine, cocaine or clonidine and the behavioral responses to intrathecally coadministered substance P were evaluated. The ED50 values for agonists administered separately and concurrently were computed and drug interactions were evaluated using isobolographic analyses. After separate administration, all the opioid and adrenergic agonists inhibited the substance P-induced behavioral responses. Upon coadministration of opioid and adrenergic agonists, a multiplicative interaction was observed between morphine or the delta agonist D-Pen2-D-Pen-5-enkephalin and the adrenergic agonists. Additive or antagonistic interactions were found between the mu agonist Tyr-D-Ala-NMe-Phe-Gly(ol) and the same adrenergic agonists. The opioid antagonist naloxone and the alpha-2 adrenergic antagonist idazoxan were given as intrathecal pretreatments at doses chosen to shift the dose-response curves of their corresponding agonist (given alone) 4- to 10-fold to the right; this always resulted in a smaller, but significant (2- to 4-fold) shift in the dose-response curve of the other agonist given alone. Intrathecal pretreatment with naloxone or idazoxan altered some interactions between the opioids and clonidine. Although naloxone blocked completely the multiplicative interaction between morphine and clonidine, idazoxan did not. Both naloxone and idazoxan changed the antagonistic interaction between Tyr-D-Ala-NMe-Phe-Gly(ol) and clonidine to a multiplicative interaction. Neither antagonist blocked the multiplicative interaction between D-Pen2-D-Pen5-enkephalin and clonidine. These results suggest that: 1) interactions between opioid and adrenergic agonists in mouse spinal cord are mediated by delta and alpha-2 receptor subtypes; 2) the synergistic interaction between morphine and alpha-2 adrenergic agonists may involve action at delta opioid receptors; and 3) antagonist action on these drug interactions is complex.
 ...
PMID:Spinal interactions between opioid and noradrenergic agonists in mice: multiplicativity involves delta and alpha-2 receptors. 137 95

Reduced glutathione (L-gamma-glutamyl-L-cysteinylglycine; GSH) is an endogenous tripeptide involved in the formation and maintenance of protein thiol groups as well as in various detoxification reactions. Because multiple receptor types contain thiol groups or disulfide bridges, effects of GSH treatments on mu-opioid, neurokinin-1/substance P, and kainic acid receptor binding sites were investigated and compared with those produced by dithiothreitol (DTT), a potent synthetic reducing agent. GSH inhibited binding more potently than did DTT at all three receptor types in porcine striatal membrane homogenates as well as in CHAPS-solubilized preparations of the mu and neurokinin-1 sites. GSH-induced inhibitory effects were associated with decreases in maximal binding capacity (Bmax) without significant alteration in apparent affinity (KD). Cysteine, the functional moiety of GSH, mimicked GSH effects albeit with lower potencies, whereas oxidized glutathione had no effects at similar concentrations. In CHAPS-solubilized preparations, the combination of low concentrations of GSH and guanylylimidodiphosphate markedly decreased the Bmax values of the binding of [3H][D-Ala2,Gly-ol5]enkephalin and [3H]substance P. This GSH-mediated mechanism may be important to prevent cell overstimulation by accelerating receptor uncoupling, desensitization, and/or internalization. This is in keeping with purported roles of GSH related to the maintenance of cellular integrity.
 ...
PMID:Modulatory role of glutathione on mu-opioid, substance P/neurokinin-1, and kainic acid receptor binding sites. 137 28

To probe the specificity of the metalloendoproteinase stromelysin toward peptide substrates, we determined kc/Km values for the stromelysin-catalyzed hydrolyses of peptides whose design was based loosely on the structure of a known SLN substrate, substance P (Arg-Pro-Lys-Pro-Gln-Gln-Phe-Phe-Gly-Leu-MetNH2, hydrolysis at Gln-Phe, kc/Km = 1700 M-1 s-1). Several noteworthy points emerge from this study: (i) Catalytic efficiency is dependent on peptide chain length with N-terminal truncation of substance P resulting in more pronounced rate-constant reductions than C-terminal truncation. These results suggest the existence of an extended active site for stromelysin. (ii) Preferences at positions P3, P2, P1, P1', and P2' are for the hydrophobic amino acids Pro, Leu, Ala, Nva, and Trp, respectively. (iii) Investigation of specificity at P3' supports our earlier hypothesis that SLN has a requirement for a hydrogen-bond donor at this position in its substrates. Based on these observations, we designed and had synthesized the fluorogenic substrate N-(2,4-dinitrophenyl)Arg-Pro-Lys-Pro-Leu-Ala-Nva-TrpNH2, whose stromelysin-catalyzed hydrolysis can be monitored continuously (kc/Km = 45,000 M-1 s-1).
 ...
PMID:Substrate specificity of the human matrix metalloproteinase stromelysin and the development of continuous fluorometric assays. 147 98

Purification and potential tachykinin and enkephalin precursor cleaving enzymes from bovine chromaffin granules was undertaken using as substrates the model precursors 35S-(Met)-beta-preprotachykinin [35S-(Met)-beta-PPT] and 35S-(Met)-preproenkephalin [35S-(Met)-PPE]. Purification by concanavalin A-Sepharose, Sephacryl S200, and chromatofocusing resulted in a chromaffin granule aspartyl protease (CGAP) that preferred the tachykinin over the enkephalin precursor. CGAP was composed of 47-, 30-, and 16.5-kDa polypeptides migrating as a single band in a nondenaturing electrophoretic gel system, and coeluting with an apparent molecular mass of 45-55 kDa by size-exclusion chromatography. These results suggest that two forms exist: a single 47-kDa polypeptide and a complex of 30 + 16.5-kDa-associated subunits. CGAP was optimally active at pH 5.0-5.5, indicating that it would be active within the acidic intragranular environment. Cleavage at basic residues was suggested by HPLC and HVE identification of 35S-(Met)-NKA-Gly-Lys as the major acid-soluble product generated from 35S-(Met)-beta-PPT. Neuropeptide K was cleaved at a Lys-Arg basic residue site, as determined by identification of proteolytic products by microsequencing and amino acid composition analyses. Structural studies showed that the three CGAP polypeptides were similar to bovine cathepsin D in NH2-terminal sequences and amino acid compositions, indicating that CGAP appears to be a cathepsin D-related protease or cathepsin D itself. The 47- and 16.5-kDa polypeptides of CGAP possessed identical NH2-terminal sequences, suggesting that the 16.5-kDa polypeptide may be derived from the 47-kDa form by proteolysis.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Purification and characterization of a cathepsin D protease from bovine chromaffin granules. 156 70

1. The classification of tachykinin receptors in the guinea-pig trachea has been investigated. This was of interest because, from previous studies, it was not clear whether the guinea-pig trachea contains either a mixture of NK1 and NK2 receptors or, alternatively, a single type of novel tachykinin receptor. 2. In the present study, the guinea-pig trachea was contracted by tachykinin agonists selective for NK1 receptors (substance P methylester (SPOMe) and GR73632) or NK2 receptors (GR64349) but not NK3 receptors (senktide). 3. Against SPOMe and GR73632, the NK1 antagonist, GR71251, behaved as a reversible competitive antagonist having apparent affinity (pKB 7.05 vs SPOMe) consistent with action at NK1 receptors. GR71251 (3 microM) did not antagonize responses to GR64349. 4. The NK2 antagonists L-659,877 and Ac-Leu-Asp-Gln-Trp-Phe-Gly-NH2 (R396) antagonized GR64349 although only R396 appeared to behave competitively (pKB 5.73). Neither L-659,877 (30 microM) nor R396 (30 microM) blocked responses to SPOMe. 5. For L-659,877 and R396, comparison was made between activity in guinea-pig trachea and in preparations known to contain tachykinin receptors predominantly of the NK2 type. In the rabbit trachea, both L-659,877 and R396 had effects similar to those in guinea-pig trachea. In contrast, in the rat colon muscularis mucosae, both L-659,877 and R396 appeared to behave competitively with pKB values against GR64349 of 7.83 and 6.90 respectively. 6. It is concluded that in guinea-pig trachea, contractile responses can be induced by activation of both NK1 and NK2 receptors. The present data are discussed with reference to the proposed existence of subtypes of the NK2 receptor.
 ...
PMID:Receptors mediating tachykinin-induced contractile responses in guinea-pig trachea. 165 74

Several N-carboxyalkyl peptides were synthesized and tested as inhibitors of pig synovial collagenase, 72-kDa gelatinase and stromelysin (matrix metalloproteinases MMP-1, MMP-2, and MMP-3). The most potent of the series, CH3CH2CH2(R,S)CH(COOH)-NH-Leu-Phe-Ala-NH2, competitively inhibited cleavage of dinitrophenyl-Pro-Leu-Gly-Leu-Trp-Ala-D-Arg-NH2 at the Gly-Leu bond by MMP-1 and MMP-2 (KI = 30 and 40 microM, respectively). A similar inhibitory potency was found for MMP-1 with soluble Type I collagen and MMP-3 with substance P as substrate. The inhibitor was coupled to EAH-Sepharose 4B through a C-terminal amide. In the presence of 2 M NaCl at pH 7.2, this matrix bound MMP-1, MMP-2, and MMP-3 from concentrated culture medium of pig synovial membranes. The enzymes coeluted at pH 4.1 and subsequently were resolved by chromatography on DEAE-Sephacel and heparin-Sepharose. Purified MMP-1 catalyzed the o-phenanthroline-sensitive cleavage of collagen into TCA and TCB fragments as well as slower hydrolysis of the alpha 2 chain. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis of MMP-1 indicated a predominant polypeptide of approximately 44 kDa and minor species of approximately 24 and 21 kDa. The 44-kDa species and one of the smaller polypeptides reacted with an antiserum to residues 195-207 of human fibroblast MMP-1, indicating that porcine MMP-1 contains a similar sequence and that the smaller components were probably derived from MMP-1. Neither MMP-2 nor MMP-3 reacted with this antiserum. Purified porcine MMP-2 degraded gelatin but not collagen and exhibited an apparent Mr of approximately 71 kDa. Additional smaller polypeptides were present, one of which may correspond to tissue inhibitor of metalloproteinases. MMP-3 showed doublets of approximately 47/46 and 26/25 kDa and cleaved substance P at the Gly6-Phe7 bond. This procedure provides a rapid means of obtaining all three MMPs from one source in approximately 15% yield each.
 ...
PMID:Application of N-carboxyalkyl peptides to the inhibition and affinity purification of the porcine matrix metalloproteinases collagenase, gelatinase, and stromelysin. 165 8


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>