Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.10.1 (ERK)
 95,504 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The cellular localization of the rat brain neutral endopeptidase (NEP, EC 3.4.24.11) was investigated by quantitative autoradiography of the enzyme inhibitor [3H]N-[(2RS)-3-hydroxyaminocarbonyl-2-benzyl-1-oxopropyl]glycine ([3H]HACBO-Gly) after lesions of the striatum, nigrostriatal and corticostriatal pathways. The effect of these lesions on NEP levels was compared with that on delta and mu opioid receptors, selectively labeled with [3H]Tyr-D-Thr-Gly-Leu-Thr ([3H]DTLET) and [3H]Tyr-D-Ala-Gly-MePhe-Glycinol ([3H]DAGO), respectively. Twenty-one days after injection of kainate in the caudate putamen (CP), the NEP level was locally decreased (52%) but the time course of this decrease was different from that of mu and delta opioid receptors: [3H]DAGO binding was diminished by 40% from day 2 whereas that of [3H]DTLET was reduced by 51% from day 7. Kainic acid injection in the CP induced in the globus pallidus (GP) and substantia nigra (SN) a distant reduction of the 3 opioid markers. Likewise after injection of colchicine in the CP, [3H]HACBO-Gly binding was decreased in the GP (60%) and SN (58%), [3H]DTLET binding was reduced by 54 and 55% in the GP and SN, respectively and [3H]DAGO labeling was diminished by 49% in the GP, and 58% in the SN. Finally, lesion of the nigrostriatal dopamine pathway by 6-hydroxydopamine did not induce any change of NEP level in the CP and GP whereas delta and mu opioid receptor levels were diminished respectively by 25 and 29% in the CP, and 45 and 39% in the GP, a new finding of the present study. Taken together these data suggest that NEP is in part associated with striatal intrinsic neurons. In the GP and SN, a large part of NEP seems to be presynaptically associated with nerve terminals endowed with mu and delta opioid receptors, which originate from efferent striatal neurons. In contrast to opioid receptors in the CP, the NEP appears not to be associated with dopaminergic nerve terminals originating from the SN. Cortical ablation did not affect any of the opioid markers.
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PMID:Neutral endopeptidase-24.11, mu and delta opioid receptors after selective brain lesions: an autoradiographic study. 282 89

The simple determination of the Neutral Metalloendopeptidase (NEP, Enkephalinase A) with the known fluorogenic substrate Dansyl-D-Ala-Gly-(pNO2)Phe-Gly is disturbed by high concentrations of the Angiotensin-Converting-Enzyme (ACE). ACE hydrolyzes this substrate too but to a smaller degree. In some tissues and body fluids a further substrate hydrolysis takes place by any indefinite proteases. Finally the enzymatic hydrolysis of the NEP-substrate is inhibited by phosphate ions. A method is proposed for the elimination of this disturbances in the NEP-determination with a phosphate-free buffer using two comparison tests with Lisinopril and o-Phenanthroline. The resulting NEP-activity is calculated very simple thereafter.
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PMID:[The determination of neutral metalloendopeptidase (enkephalinase A) in biological material]. 285 71

A growth hormone-dependent binding protein for insulin-like growth factors (IGF-I and IGF-II) has been isolated from human plasma. Analyzed on SDS gels, the preparation contained a major protein band of 53 kDa, and a minor band of 47 kDa. After transfer to nitrocellulose, both species bound iodinated IGF-I, and could be detected using an antibody raised against the purified preparation. In contrast, an IGF binding protein purified from human amniotic fluid bound IGF-I but was not detectable immunologically. The amino acid comparison of the plasma binding protein preparation was different from that reported for amniotic fluid and HEP G2 hepatoma proteins, and the unique amino-terminal sequence, Gly-Ala-Ser-Ser-Ala-Gly-Leu-Gly-Pro-Val-, was different from that of the amniotic fluid and hepatoma proteins. This study indicates that the growth hormone-dependent IGF binding protein of human plasma is structurally and immunologically distinct from other IGF binding proteins.
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PMID:Growth hormone-dependent insulin-like growth factor (IGF) binding protein from human plasma differs from other human IGF binding proteins. 294 61

The effect of soman poisoning on the levels of methionine enkephalin and beta-endorphin in mice and rats were determined. Soman poisoning produced no significant effect on methionine enkephalin levels in the striatum of rats or mice or beta-endorphin levels in the pituitary gland of mice. In rats beta-endorphin levels were significantly reduced 24 hr post soman poisoning, but returned to control levels by 48 hr. In vitro, the hydrolysis of leucine enkephalin by aminopeptidase was virtually complete by 30 min and found to be the major route of degradation. The release of TYR-GLY-GLY in the presence or absence of puromycin (10 microM) was found to be low (less than or equal to 2.0%). A minor effect on TYR release in the presence of GLY-GLY-PHE-MET (50 microM) was insignificant. Preincubation of mouse striatum homogenates with soman (1 or 10 microM) did not inhibit the hydrolysis of leucine enkephalin. These results suggest that the long term antinociception following soman exposure is not due to either altered concentration of endogenous opioid-like substances or inhibition of the enzymes responsible for their degradation.
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PMID:Role of endogenous opioids in soman (pinacolyl methylphosphonofluoridate)-induced antinociception. 295 88

The neutral endopeptidase NEP 24.11 (enkephalinase) has been visualized in human spinal cord by in vitro autoradiography using [3H]HACBO-Gly as a radiolabelled probe. The specific binding was present in the substantia gelatinosa and particularly dense in meninges surrounding the spinal cord. Enzymatic studies using [3H][D-Ala2, Leu]enkephalin as substrate confirmed the presence of NEP in dura and pia mater of human tissue. In addition, the human meninges were shown to contain high concentrations of angiotensin-converting enzyme (ACE) and aminopeptidases. The three enzymes have also been detected in rat tissues but their distribution pattern differs from that of human tissue. In dura mater, 45% of the [Leu]enkephalin hydrolysis was due to enkephalinase and 38% to bestatin-sensitive aminopeptidases. In contrast in pia mater aminopeptidases were more efficient in hydrolyzing enkephalin. The possible role of these enzymes in the meninges could be to maintain the homeostatic concentration of neuropeptides in the central nervous system.
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PMID:Enkephalin-degrading enzymes and angiotensin-converting enzyme in human and rat meninges. 303 68

A synthetic chimeric gene, coding for the human epidermal growth factor fused to the signal peptide of Escherichia coli alkaline phosphatase, was cloned into E. coli under the transcriptional control of the trp-lac (tac) promoter. Following induction with isopropylthiogalactoside, the secretion of the correctly processed protein product into the bacterial periplasm was detected and quantitated by its specific binding to the epidermal growth factor receptor. The purified protein was identical to authentic human epidermal growth factor in size, amino acid composition, primary sequence, receptor binding, and stimulation of receptor protein-tyrosine kinase activity. Based on interspecies homologies, structural considerations, and reported studies with peptide fragments, structure-function analysis was initiated with alterations of targeted amino acid residues by oligonucleotide-directed mutagenesis. The receptor binding affinity of each mutant, relative to the wild type, was measured by both radioreceptor competition and receptor tyrosine kinase stimulation assays. In general, the values obtained by the two methods were in agreement for each species of epidermal growth factor and followed the order: wild type greater than Glu24----Gly greater than Asp27----Gly much greater than Pro7----Thr greater than Tyr29----Gly greater than Leu47----His. The relatively low values obtained with the last two mutants suggest that Tyr29 and Leu47 may be important for the biological activity of human epidermal growth factor.
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PMID:Cloning of authentic human epidermal growth factor as a bacterial secretory protein and its initial structure-function analysis by site-directed mutagenesis. 304 17

An antiserum (ARK-1) specific to the gonadotropin-releasing hormone precursor (proGnRH) was produced by immunizing with a synthetic peptide (proGnRH 6-16; Gly-Leu-Arg-Pro-Gly-Gly-Lys-Arg-Asp-Ala-Glu) which bridges the proteolytic cleavage site of proGnRH. When used in the radioimmunoassay, ARK-1 bound 25% of the iodinated 5-16 fragment at a 1:30,000 dilution with a sensitivity of 1 pg/tube. Using immunohistochemical techniques, we observed that in serial and the same sections through the preoptic-basal hypothalamus (POA-BH), the precursor molecule was primarily present in the cell soma, whereas GnRH was found in the cell soma, nerve fibers, and terminals of the same neurons. These data indicate that the processing of proGnRH to biologically active peptides (e.g., GnRH) in the rhesus macaque and the baboon POA-BH primarily occurs in the cell soma.
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PMID:Immunohistochemical demonstration of proGnRH and GnRH in the preoptic-basal hypothalamus of the primate. 330 46

A porcine brain dipeptidyl-aminopeptidase (DAP) has been purified more than 2400-fold from a crude mitochondrial fraction containing synaptosomes. This enzyme catalyzes the release of free Tyr-Gly from Leu-enkephalin (Km = 2.5 microM) with an optimal activity between pH 6.0 and pH 8.0. The enzyme appears homogeneous as judged by sodium dodecyl sulfate-polyacrylamide gel electrophoresis devoid of detectable contaminating aminopeptidase activities. The native enzyme is a monomeric protein with a molecular weight of 51,000 +/- 1,000 and an isoelectric point of 4.6 +/- 0.1. This enzyme cosediments with synaptosomes on a Ficoll-sucrose gradient and is partially associated with synaptic plasma membranes. Its activity is inhibited by the metal-chelating agents ethylenediaminetetraacetate and o-phenanthroline. It is not inhibited by the OH-reactive agent phenylmethanesulfonyl fluoride and SH-reactive agents such as p-(chloromercuri)benzoate and N-ethylmaleimide. Among the various biologically active peptides tested, the purified enzyme releases efficiently the N-terminal dipeptide moiety from enkephalins, Trp-Met-Asp-Phe-NH2 (CCK4), and Gly-Trp-Met-Asp-Phe-NH2 (CCK5). At variance, the native peptides CCK8, substance P, neurotensin, and angiotensin II are not cleaved by the DAP. This enzyme is different from other unspecific DAPs, as well as from enkephalin-degrading DAPs previously reported, by its molecular weight and substrate specificity.
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PMID:Purification and characterization of an enkephalin-degrading dipeptidyl-aminopeptidase from porcine brain. 381 77

Recent developments on neutral endopeptidase (NEP, EC 3.4.24.11) are described. These include (1) the development of a novel colorimetric assay with a chromogenic substrate (Glutaryl-Gly-Gly-Phe-2-naphthylamide) coupled with aminopeptidase M (EC 3.4.11.2). (2) A detergent form of the pig kidney enzyme has been purified by immuno-adsorbent chromatography and its molecular properties compared with other forms of the enzyme from rabbit kidney and pig intestine. (3) Rat kidney microvilli contain two endopeptidases of about equal activity when assayed with [125I]iodo-insulin B chain as substrate. One is similar to the rabbit and pig endopeptidases in being sensitive to inhibition by phosphoamidon. The other is insensitive to the inhibitor, though susceptible to chelating agents. The two enzymes are resolvable and have been partially characterized. (4) Endopeptidases of the phosphoramidon-sensitive type are present in various tissues in addition to the principal locations in brush borders of kidney and intestine.
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PMID:Microvillar membrane neutral endopeptidases. 612 11

Angiotensin I converting enzyme (ACE) and neutral endopeptidase ("enkephalinase"; NEP), were purified to homogeneity from human kidney. NEP cleaved substance P (SP) at Gln6-Phe7,-Phe8, and Gly9-Leu10 and neurotensin (NT) at Pro10-Tyr11 and Tyr11-Ile12. NEP hydrolyzed 0.1 mM SP, NT and their C-terminal fragments at the following rates (mumol/min/mg): SP1-11 = 7.8, SP4-11 = 11.7, SP5-11 = 15.4, SP6-11 = 15.6, SP8-11 = 6.7, NT1-13 = 2.9, and NT8-13 = 4.0. Purified ACE rapidly inactivated SP as measured in bioassay. HPLC analysis showed that ACE cleaved SP at Phe8-Gly9 and Gly9-Leu10 to release C-terminal tri- and dipeptide (ratio = 4:1). The hydrolysis was Cl- dependent and inhibited by captopril. ACE released mainly C-terminal tripeptide from SP methyl ester, but only dipeptide from SP free acid. Modification of arginine residues in ACE with cyclohexanedione or butanedione similarly inhibited hydrolysis of SP, bradykinin and Bz-Gly-Phe-Arg (80-93%) indicating an active site arginine is required for hydrolysis of SP. ACE hydrolyzed NT at Tyr11-Ile12 to release Ile12-Leu13. SP, NT and their derivatives (0.1 mM) were cleaved by ACE at the following rates (mumol/min/mg): SP1-11 = 1.2, SP methyl ester = 0.7, SP free acid = 8.5, SP4-11 = 2.4, SP5-11 = 0.9, SP6-11 = 1.4, SP8-11 = 0, NT1-13 = 0.2, and NT8-13 = 1.3. Peptide substrates were used as inhibitors of ACE (substrate = FA-Phe-Gly-Gly) and NEP (substrate = Leu5-enkephalin).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Hydrolysis of substance p and neurotensin by converting enzyme and neutral endopeptidase. 620 35


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