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)

Systematic analysis of the hydrolysis of benzyloxycarbonyl (Cbz)-dipeptides by cathepsin A [EC 3.4.12.1] purified from rat liver lysosomes showed that multiple forms of cathepsin A preferentially cleave peptide bonds with leucine, methionine, and phenylalanine. Cbz-Met-Met, -Met-Phe, -Phe-Met, and -Phe-Ala were hydrolyzed 6 to 8 times faster than the standard substrates, Cbz-Glu-Phe and Cbz-Glu-Tyr. The pH optima of the hydrolyses were 4.6 to 5.8. Hydrolysis of peptide bonds with glycine, isoleucine, and proline was very slow, but the rate depended on the nature of the adjacent amino acids. Proteins such as albumin, cytochrome c, gamma-globulin, hemoglobin, histone, myoglobin, and myosin were scarecely degraded. Peptide hormones, such as glucagon and adrenocorticotropic hormone (ACTH) were hydrolyzed markedly with optimum pH's of 4.5 and 4.6, respectively. Angiotensin I, II, bradykinin, Lys- and Met-Lysbradykinin (kallidin and Met-kallidin), and substance P were also hydrolyzed at appreciable rates. pH optima for these peptide hormones were 5.2 to 5.6. On the other hand, insulin and its A chain, luteinizing hormone-releasing hormone (LH-RH), oxytocin and vasopressin were cleaved slowly. In the hydrolyses of glucagon and other peptides, multiple forms of rat liver lysosomal cathepsin A again showed a carboxypeptidase nature, cleaving peptide bonds sequentially from the carboxyl terminal. Almost all of the amino acids were cleaved on prolonged incubation. Vaso-activites of angiotensin II and bradykinin were rapidly lost on hydrolysis by cathepsin A. Lysosomal cathepsin C [dipeptidylaminopeptidase I, EC 3.4.14.1] also activated angiotensin II, but did not inactive bradykinin. Cathepsin A, therefore, can be regarded as one of the lysosomal angiotensinases and kinases. No distinct differences were observed between the multiple forms of cathepsin A in these hydrolyses and inactivations of peptides.
 ...
PMID:Studies on cathepsins of rat liver lysosomes. III. Hydrolysis of peptides, and inactivation of angiotensin and bradykinin by cathepsin A. 1 61

The data presented concern the chemistry and biology of cardiotrop peptides and proteins isolated by us from the hypothalamus. The molecular mechanisms of the effect of neurohormone "C" (NC) as well as of a new cardiotrop hexapeptide from cattle hypothalamus are discussed. In in vitro studies on homogenates NC has been found to inhibit greatly not only 3'--5'-cyclo-AMP phosphodiesterase activity of brain and heart but also 3'--5'-cyclo-GMP phosphodiesterase activity. NC has been shown to be bound to specific proteins and to the regulatory unit of cyclo-AMP-dependent histone kinase of brain. It seems to compete with cyclo-AMP for the same proteins and is considered to be a regulator of intracellular cyclic nucleotides. NC has been shown to be combined to specific proteins in brain with non covalent bonds. A new cardiotrop hexapeptide has been shown to be present in bovine hypothalamus and its chemical structure has been found to be Tyr-Leu-Gly-Arg-Pro-Gly-amide. The acetylated form of this hexapeptide, which may be also present in brain, is much more active. The radioimmunochemical experiments carried out with antiserum 744 (from prof. Schally) by us have confirmed the existence of this hexapeptide and other fragments of LH-RH in the bovine hypothalamus. The effect of this hexapeptide on cardiac function and metabolism has been compared with a number of polypeptides (luliberin fragments). The hexapeptide has been shown to have not only cardiotropic but also a hypoglycaemic effect. It enhances the secretion of insulin and counteracts the inhibitory action of somatostatin on the insular apparatus. The hexapeptide produces significant changes in the activities of phosphorylase a and b as well as in that of phosphoprotein phosphatases. It reduces the amount of kinines in blood. Certain fractions of substance P, have been shown to have cardiotrop actitivty--they increase the rate of blood leaving the heart. The organotrop effects of a number of peptide neurohormones are discussed in connection with the hexapeptide. The results obtained have shown that the mechanisms underlying the effects of the cardioactive substances found by us are quite different. The data presented show that in brain a number of chemical factors (mainly peptides) are formed, which are involved in the regulation of heart function.
 ...
PMID:[Chemistry and biology of hypothalamic cardioactive proteins and peptides]. 22 93

The present study has extended histochemical and functional investigations into rat mast cell heterogeneity using isolated mast cells from four connective tissue locations; the peritoneum, mesentery, lung and skin. On histological examination, mast cells from these locations displayed a range of phenotypes following formalin fixation and staining with Alcian blue/safranin O, suggesting the existence of both chondroitin sulphate and heparin proteoglycans in varying proportions in these cell types. Functional studies using the structurally diverse polycationic secretagogues, compound 48/80, the polyamino acids, polymyxin B, substance P, ACTH1-24, mastoparan, protamine sulphate, histone, d-tubocurarine and ranitidine confirmed the existence of such phenotypic gradation. This investigation highlights the inappropriate usage of the terms CTMC and MMC which represent two phenotypic extremes between which a gradation of phenotypes clearly exists.
 ...
PMID:Mast cell heterogeneity: evidence that mast cells isolated from various connective tissue locations in the rat display markedly graded phenotypes. 137 40

It has been assumed that the histamine release from mast cells induced by various neuropeptides or basic protein plays some important roles in the development of the hyperreactivity of airways. In the present study, the mechanisms of the histamine release induced by neuropeptides and histone were investigated. Substance P, somatostatin, neurotensin or histone induced histamine release from isolated rat peritoneal mast cells even in the Ca free medium; Ca2+ release from intracellular Ca store was detected very significantly. In order to study the interaction between neuropeptides and phospholipid bilayer of cell membrane, model membrane systems were used. It was indicated that the interaction between basic amino acid residues of neuropeptides and acidic portion in the lipid bilayer caused the conformational changes of neuropeptides from the random coil in the water to the beta-form in the lipids. At the same time, hydrophobic amino acid residues may interact with the hydrophobic region in the lipid bilayer of cell membrane and induce the membrane perturbation, which may cause an increase of the permeability of the membrane. Subsequently, it became evident that after an increase in intracellular Ca2+ concentration, the cytoskeletons inside the mast cell were activated so as to extrude the granules out of the cell.
 ...
PMID:[Mast cell]. 170 50

An increase in inositol 1, 4, 5-trisphosphate (IP3) formation in rat mast cells precedes an elevation in intracellular Ca2+ levels, which triggers the process(es) leading to histamine release. By means of a transmission electron microscope, it was revealed that when permeabilized mast cells were exposed to potassium antimonate, antimonate precipitates in the endoplasmic reticulum (ER) in the form of calcium antimonate, indicating that the ER is the intracellular Ca store in rat mast cells. IP3 at concentrations higher than 0.5 microM preferentially releases Ca2+ from the isolated ER of mast cells. GTP was also effective in releasing Ca2+ from the ER. IP3-induced Ca2+ release was inhibited by pretreatments with cAMP and antiallergic drugs. An increase in the intracellular Ca2+ concentration may lead to an activation of calmodulin, C kinase and cytoskeletal elements in sequence. Furthermore, microtubules may play an important role in the process(es) leading to Ca2+ release from the intracellular Ca store and subsequent histamine release, without affecting IP3 formation. In contrast, microfilaments seem to participate not only in the extrusion but also in the reincorporation of the mast cell granules, having no influence on intracellular Ca2+ release. Substance P (SP) is one of the most effective neuropeptides for releasing histamine from mast cells. Structure-activity relationship studies indicate that basicity at the N-terminal and hydrophobicity at the C-terminal are requisite for its histamine releasing activity. SP effectively released Ca2+ from the intracellular Ca store. The site of action of SP on the mast cell surface seems to be the same as that of compound 48/80. Eosinophil major basic protein (MBP) and histone are also effective for releasing histamine. The cDNA sequences of two subclasses of guinea pig MBP have been determined. These proteins may be released at the site of inflammation from the cells activated by the chemical mediators released from mast cells, and consequently, mast cell activation was reinforced. Such cell-to-cell interaction may be the reason for the augmentation of inflammation.
 ...
PMID:[Recent advances in the research on histamine release]. 172 Jul 58

Histone 10 to 50 micrograms/ml released histamine from rat peritoneal mast cells in the absence of extracellular calcium. Extracellular calcium, 1 mM produced a slight shift of the histone dose-response curve to the right. In the absence of extracellular calcium, the histamine release-response to combined stimulation with histone and substance P was saturable. Neither histone nor substance P elicited any further response when one of these agonists alone was already eliciting a maximum response, although the cells were capable of a greater degree of histamine release in the presence of compound 48/80. In the presence of extracellular calcium, substance P at a concentration not by itself producing a response, acted synergistically with histone to induce histamine release. The substance P antagonist, SP-A, inhibited histamine release by histone. The phorbol ester, TPA, released histamine in a dose-dependent manner and this response was inhibited by SP-A. It is suggested that substance P and histone interact with a common site to release histamine and the role of protein kinase C in this release mechanism is discussed.
 ...
PMID:Histamine release induced by histone and phorbol ester from rat peritoneal mast cells. 241 41

The pattern of endogenous protein phosphorylation during stimulation of rat peritoneal mast cells by two types of agonists has been compared. Compound 48/80, substance P and histone, which do not require the presence of external Ca2+ to trigger histamine release, induced a similar profile of phosphorylation comprising an increased phosphorylation of a 35,000 molecular weight (MW) protein and dephosphorylation of a 15,000 MW protein. The same profile was seen when the cells were stimulated with phorbol-12-myristate-13-acetate. The phorbol ester also induced histamine release, although less than that caused by the other secretagogues. The pattern of phosphorylation shared by both the phorbol ester and the basic secretagogues represented only part of that observed when the cells were stimulated in a Ca2+-free medium with anti-IgE. Under those conditions, two additional proteins of 68,000 and 56,000 MW became phosphorylated. The phosphorylation of these two proteins increased when anti-IgE was applied in the presence of Ca2+. In contrast, the extent of phosphorylation of the 35,000 MW protein was diminished. Both the basic secretagogues and anti-IgE, but not the phorbol ester, also enhanced the production of phosphatidic acid, indicating that diacylglycerol was generated. This process was independent of the presence of external Ca2+. It is suggested that protein kinase C activation is responsible for the phosphorylation observed with the basic secretagogues but not entirely with IgE-directed ligands.
 ...
PMID:Protein and diacylglycerol phosphorylation in the stimulus-secretion coupling of rat mast cells. 243 45

Calmodulin, a ubiquitous Ca2+-binding regulatory protein, is phosphorylated exclusively on tyrosine-99 in an insulin-dependent manner by wheat germ lectin-purified preparations of insulin receptors from rat adipocyte plasma membranes. Calmodulin is phosphorylated in the presence of polylysine, histone Hf2b, and protamine sulfate, but not in the absence of these cofactors or in the presence of other basic compounds known to interact with calmodulin, such as mellitin, myelin basic protein, chlorpromazine, trifluoperazine, substance P, glucagon, polyarginine, mastoparin, beta-endorphin, spermine, spermidine, and putrescine. The incorporation of 32P into calmodulin, expressed in terms of moles of phosphate per moles of calmodulin and assayed at calmodulin concentrations of 1.2 and 0.06 microM, is 0.023 + 0.002 and 0.046 + 0.006, respectively. This low stoichiometry is likely due to the relative impurity of the receptor preparation, as similar studies not shown here, using highly purified human insulin receptors, yield a stoichiometry of 1 mol phosphate/mol calmodulin. The time course of phosphorylation is characterized by a short initial lag phase of approximately 5 min, a rapid linear rate from approximately 5 to 40 min, with a steady state of 32P incorporation being approached at approximately 60 min. The K0.5 for ATP is 104 + 18 microM. Phosphorylated calmodulin is partially purified by HPLC on a C4 column using a trifluoroacetic acid/acetonitrile gradient solvent system. Phosphoamino acid analysis and limited thrombin digestion were used to determine that the site of insulin-induced phosphorylation of calmodulin is exclusively on tyrosine-99 regardless of the basic protein cofactor used. Phosphorylated calmodulin does not exhibit the characteristic Ca2+ shift normally observed with calmodulin in electrophoretic gels, an observation that is consistent with this modification affecting the biological activity of the molecule. Thus, the tyrosine phosphorylation of calmodulin represents a potentially important post-translational modification altering calmodulin's ability to regulate a variety of enzymes involved in growth, differentiation, and metabolic regulation.
 ...
PMID:The in vitro phosphorylation of calmodulin by the insulin receptor tyrosine kinase. 341 47

The ability of washed whole cells of Treponema denticola ATCC 35405 to hydrolyze (inactivate) substance P, bradykinin, and angiotensin I was studied. Substance P was attacked primarily at the Phe-8-Gly-9 bond by a chymotrypsin-like proteinase (CTLP), at Pro-4-Gln-5 by an endo-acting prolyl oligopeptidase (POPase), and at Gln-5-Gln-6 by an endopeptidase (FALGPA-peptidase). Bradykinin was cleaved at Phe-5-Ser-6 by the FALGPA-peptidase and at Pro-7-Phe-8 by the POPase. Angiotensin I was rapidly converted to angiotensin II by the CTLP, and both angiotensin I and angiotensin II were further hydrolyzed at Pro-7-Phe-8 by the POPase. All these enzymes were assumed to be cell associated and were easily extracted with a mild (0.05 to 0.1%) Triton X-100 treatment. Because it was conceivable that the hydrolysis of substance P at the Phe-8-Gly-9 bond was catalyzed by a CTLP described earlier (V.-J. Uitto, D. Grenier, E. C. S. Chan, and B. C. McBride, Infect. Immun. 56:2717-2722, 1988), the enzyme was purified to homogeneity by means of conventional fast protein liquid chromatography procedures. For kinetic studies, Phe-8(4-nitro)-substance P (NSP) (absorption maximum at 309.2 nm, epsilon = 545 M-1 cm-1) was synthesized to replace substance P as a substrate in kinetic studies. In reversed-phase chromatography, both NSP and substance P gave identical results with both whole cells and the purified enzyme. The CTLP has a mass of 95 kDa, and its activity is suggested to be based on an active seryl residue, on an active imidazole group, and on an active carboxyl group but not on metal cations. The enzyme hydrolyzes N-succinyl-L-Ala-L-Ala-L-Pro-L-Phe-p-nitroaniline (SAAPFNA, a typical chymotrypsin substrate) at a high rate and several proteins, such as calf thymus histone, human plasma fibrinogen, milk caseins, and gelatin. Among the substrates tested, substance P showed the highest affinity (Km = 0.22 mM) for the purified enzyme. Depending on conditions, clinically applicable chlorhexidine levels (3.2 mmol/liter, or 0.2%) strongly activated (up to fourfold) the hydrolysis of SAAPFNA by whole cells and the purified CTLP. The hydrolysis of NSP by whole cells and purified CTLP was slightly inhibited by chlorhexidine. The results demonstrated the versatility and the effectiveness of the outer membrane of T. denticola in occasioning a rapid breakdown and inactivation of human bioactive peptides and other peptidolytic catalyses.(ABSTRACT TRUNCATED AT 400 WORDS)
 ...
PMID:Role of the chymotrypsin-like membrane-associated proteinase from Treponema denticola ATCC 35405 in inactivation of bioactive peptides. 754 86

Existing pharmacological treatments for bipolar disorder (BPD) and major depressive disorder (MDD) are often insufficient for many patients. Here we describe a number of targets/compounds that clinical and preclinical studies suggest could result in putative novel treatments for mood disorders. These include: (1) glycogen synthase kinase-3 (GSK-3) and protein kinase C (PKC), (2) the purinergic system, (3) histone deacetylases (HDACs), (4) the melatonergic system, (5) the tachykinin neuropeptides system, (6) the glutamatergic system, and (7) oxidative stress and bioenergetics. The paper reviews data on new compounds that have shown antimanic or antidepressant effects in subjects with mood disorders, or similar effects in preclinical animal models. Overall, an improved understanding of the neurobiological underpinnings of mood disorders is critical in order to develop targeted treatments that are more effective, act more rapidly, and are better tolerated than currently available therapies.
 ...
PMID:New therapeutic targets for mood disorders. 2041 80


1 2 Next >>