Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.24.11 (CD10)
 9,792 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The neutral endopeptidase EC 3.4.24.11, also designated enkephalinase, has been visualized by in vitro autoradiography using the tritiated inhibitor [3H]-N-[(2RS)-3-hydroxyaminocarbonyl-2-benzyl-1-oxopropyl] glycine, ([3H]HACBO-Gly). Specific binding of [3H]HACBO-Gly (Kd = 0.4 +/- 0.05 nM) corresponding to 85% of the total binding to brain slices was inhibited by 1 microM thiorphan, a selective inhibitor of enkephalinase, but remained unchanged in the presence of captopril, a selective inhibitor of angiotensin-converting enzyme. Very high levels of [3H]HACBO-Gly binding were found in the choroid plexus and the substantia nigra. High levels were present in the caudate putamen, globus pallidus, nucleus accumbens, olfactory tubercle, and in the substantia gelatinosa of the spinal cord. Moderate densities were found in parts of the amygdala, the periaqueductal gray matter, the interpeduncular nucleus, and the molecular layer of the cerebellum. The distribution of enkephalinase was compared to that of mu and delta opioid receptors, selectively labeled with [3H]Tyr-D-Ala-Gly-MePhe-glycinol and [3H]Tyr-D-Thr-Gly-Phe-Leu-Thr, respectively. In the caudate putamen, [3H]HACBO-Gly binding overlapped the clustered mu sites but appeared more closely related to the diffusely distributed delta sites. High levels of enkephalinase and mu opioid binding sites were present at the level of the periaqueductal gray matter and in the substantia gelatinosa of the spinal cord, regions where only sparse delta opioid receptors could be detected. The association of enkephalinase with delta and mu opioid receptors in these areas is consistent with the observed role of the enzyme in regulating the effects of opioid peptides in striatal dopamine release and analgesia, respectively. Except for the choroid plexus and the cerebellum, the close similarity observed in numerous rat brain areas between the distribution of enkephalinase and that of mu and/or delta opioid binding sites could account for most of the pharmacological effects elicited by enkephalinase inhibitors.
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PMID:Autoradiographic comparison of the distribution of the neutral endopeptidase "enkephalinase" and of mu and delta opioid receptors in rat brain. 300 54

The electric organ of Torpedo marmorata contains a membrane-bound, captopril-sensitive metallopeptidase that resembles mammalian angiotensin converting enzyme (peptidyl dipeptidase A; EC 3.4.15.1). The Torpedo enzyme has now been purified to apparent homogeneity from electric organ by a procedure involving affinity chromatography using the selective inhibitor lisinopril immobilised to Sepharose via a 28-A spacer arm. The purified protein, like the mammalian enzyme, acted as a peptidyl dipeptidase in cleaving dipeptides from the C-terminus of a variety of peptide substrates, including angiotensin I, bradykinin, [Met5]enkephalin, [Leu5]enkephalin, and the model substrate hippuryl (benzoylglycyl; BzGly)-His-Leu. The hydrolysis of BzGly-His-Leu was activated by Cl-. Enzyme activity was inhibited by classical angiotensin converting enzyme inhibitors, including captopril, enalaprilat (MK422), and lisinopril (MK521). Torpedo angiotensin converting enzyme, like its mammalian counterpart, was also able to act as an endopeptidase in hydrolysing the amidated neuropeptide substance P. Hydrolysis of substance P occurred primarily at the Phe8-Gly9 bond with release of the C-terminal tripeptide, Gly-Leu-MetNH2, and this hydrolysis was blocked by selective inhibitors. The Torpedo enzyme was recognised by a polyclonal antibody to pig kidney angiotensin converting enzyme on immunoelectrophoretic (Western) blot analysis. Thus, on the basis of substrate specificity, inhibitor sensitivity, and immunological criteria, the Torpedo enzyme closely resembles mammalian angiotensin converting enzyme. However, the Torpedo enzyme appears somewhat larger (Mr = 190,000) than the pig kidney enzyme (Mr = 180,000) on sodium dodecyl sulphate-polyacrylamide gel electrophoresis. The endogenous peptide substrate(s) for Torpedo electric organ angiotensin converting enzyme and the physiological role of the enzyme in this tissue remain to be evaluated.
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PMID:Purification and characterization of a peptidyl dipeptidase resembling angiotensin converting enzyme from the electric organ of Torpedo marmorata. 302 62

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

The endogenous opioid peptides all contain the enkephalin sequence Tyr-Gly-Gly-Phe-Met and Tyr-Gly-Gly-Phe-Leu at their aminoterminus. Three distinct families of these peptides (endorphins, enkephalins and dynorphins) are present in different neuronal pathways within the central nervous system. Molecular genetics have shown that these three families of opioid peptides are derived from three distinct precursors. Pro-opiomelanocortin gives rise to the endorphins, as well as adrenocorticotropic hormone (ACTH) and the melanotropic hormones (MSH's). [Met] enkephalin, [Leu] enkephalin and the related heptapeptide [Met] enkephalin-Arg6-Phe7 and octapeptide [Met] enkephalin-Arg6-Gly7-Leu8 are derived from proenkephalin. The third family is derived from prodynorphin and includes dynorphin A, dynorphin B (also known as rimorphin) and alpha- and beta-neo-endorphin. The structure of the genes coding for these precursors are similar, suggesting the possibility of one common ancestral gene. The most common scheme for enzymatic maturation of precursors proposes the action of a trypsin-like endopeptidase followed by a carboxypeptidase B-like exopeptidase. However, we have provided evidence that this combination of trypsin-like and carboxypeptidase B-like enzymes may not be the only mechanism for liberating enkephalin from low molecular weight enkephalin-containing peptides. Indeed, endo-oligopeptidase A, an enzyme, known to hydrolyze the Phe5-Ser6 bond of bradykinin and the Arg8-Arg9 bond of neurotensin, has been shown to produce, by a single cleavage, [Leu] enkephalin or [Met] enkephalin from small enkephalin-containing peptides, (Camargo et al., 1987, J. Neurochem. 48, 1258-1263).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Biosynthesis of opioid peptides]. 305 81

Locust adipokinetic hormone (AKH, pGlu-Leu-Asn-Phe-Thr-Pro-Asn-Trp-Gly-Thr-NH2) was used as the substrate to measure neuropeptide-degrading endopeptidase activity in neutral membranes from ganglia of the locust Schistocerca gregaria. Initial hydrolysis of AKH at neural pH by peptidases of washed neural membranes generated pGlu-Leu-Asn and Phe-Thr-Pro-Asn-Trp-Gly-Thr-NH2 as primary metabolites, demonstrating that degradation was initiated by cleavage of the Asn-Phe bond. Amastatin protected the C-terminal fragment from further metabolism by aminopeptidase activity without inhibiting AKH degradation. The same fragments were generated on incubation of AKH with purified pig kidney endopeptidase 24.11, and enzyme known to cleave peptide bonds that involve the amino group of hydrophobic amino acids. Phosphoramidon (10 microM), a selective inhibitor of mammalian endopeptidase 24.11, partially inhibited the endopeptidase activity of locust neural membranes. This phosphoramidon-sensitive activity was shown to enriched in a synaptic membrane preparation with around 80% of the activity being inhibited by 10 microM-phosphoramidon (IC50 = 0.2 microM). The synaptic endopeptidase was also inhibited by 1 mM-EDTA, 1 mM-1,10-phenanthroline and 1 microM-thiorphan, and the activity was maximal between pH 7.3 and 8.0. Localization of the phosphoramidon-sensitive enzyme in synaptic membranes is consistent with a physiological role for this endopeptidase in the metabolism of insect peptides at the synapse.
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PMID:Neuropeptide-degrading endopeptidase activity of locust (Schistocerca gregaria) synaptic membranes. 306 56

Neutral proteases of Plasmodium sp erythrocytic stages were studied by means of a sensitive fluorogenic method and gelatin-SDS-PAGE. The substrates gluconoyl-Val-Leu-Gly-Lys(or Arg)-3-amido-9-ethylcarbazole were selectively hydrolyzed by an endopeptidase from rodent Plasmodium berghei (Pb) and Plasmodium chabaudi (Pc) and from human Plasmodium falciparum (Pf) parasites. These endopeptidases were purified from 100,000-g soluble schizont extract by high pressure liquid chromatography; they have a similar Mr of 68,000 in SDS-PAGE, and an optimal activity at pH 7.4. The Pb 68 and Pf 68 endopeptidases were localized in schizonts and also in merozoites as shown by indirect immunofluorescence on Pb merozoites and by the identification of the Pf 68 endopeptidase activity in free viable merozoites. The Pb 68 and Pf 68 endopeptidases belong to the class of cysteine proteases. Analysis by gelatin-SDS-PAGE of a Pb 68 endopeptidase-enriched fraction showed a reproducible 95,000 proteolytic band. The initial extracts showed a similar 95,000 proteolytic band, and also 2 other 90,000 and 85,000 major bands. During reinvasion experiments, it was possible to recover a 95,000 and a 40,000 protease band from supernates of cultures grown in a semidefined medium without serum. Hydrophilic peptide derivatives related to the substrate of Pf 68 endopeptidase are shown to be potential inhibitors of the Pf reinvasion process in vitro.
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PMID:Neutral proteases involved in the reinvasion of erythrocytes by Plasmodium merozoites. 306 1

The tripeptide Tyr-Gly-Gly (YGG) was established as an endogenous constituent in rat brain. Its origin from enkephalin neurons is suggested by its regional distribution paralleling that of (Met5)-enkephalin (YGGFM), its decrease following kainate-induced ablation of the striato-pallidal neurons and its enhanced formation following depolarization of pallidal slices. Enkephalinase (EC 3.4.24.11) is selectively responsible for endogenous YGG formation in vitro and in vivo.
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PMID:The endogenous tripeptide Tyr-Gly-Gly as an extracellular metabolite of enkephalins in rat brain: origin and metabolism. 312 44

A serine endopeptidase was characterized as a major inactivating enzyme for endogenous cholecystokinin (CCK) in brain. CCK-8 released by depolarization of slices of rat cerebral cortex, as measured by its immunoreactivity (CCK-ir), undergoes extensive degradation (approximately 85% of the amount released) before reaching the incubation medium. However, recovery of CCK-ir is enhanced up to 3-fold in the presence of serine-alkylating reagents (i.e., phenylmethylsulfonyl fluoride) as well as selected active site-directed inactivators (i.e., peptide chloromethyl ketones) or transition-state inhibitors (i.e., peptide boronic acids) of serine peptidases. Among these compounds, elastase inhibitors were the most potent protecting agents, whereas trypsin or chymotrypsin inhibitors were ineffective. HPLC analysis of endogenous CCK-ir recovered in media of depolarized slices indicated that endogenous CCK-5 [CCK-(29-33)-pentapeptide] was the most abundant fragment and that its formation was strongly decreased in the presence of an elastase inhibitor. HPLC analysis of fragments formed upon incubation of exogenous CCK-8 [CCK-(26-33)-octapeptide] with brain slices showed CCK-5, Gly-Trp-Met, and Trp-Met to be major metabolites of CCK-8 whose formation was prevented or at least diminished in the presence of the elastase inhibitor. It is concluded that there is an elastase-like serine endopeptidase in brain that cleaves the two peptide bonds of CCK-8 where the carboxyl group is donated by a methionine residue and constitutes a major inactivation ectoenzyme for the neuropeptide.
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PMID:A serine peptidase responsible for the inactivation of endogenous cholecystokinin in brain. 318 27

We designed phethiol (1-amino-1-benzyl-2-mercaptoethane) as a potent and selective inhibitor of Zn-containing aminopeptidases. This compound inhibited purified aminopeptidase M (EC.3.4.11.2) with a Ki of 5 nM but was at least 1000 times less potent against other metallopeptidases comprising angiotensin-converting enzyme EC 3.4.15.1), enkephalinase (EC 3.4.24.11), thermolysin (EC 3.4.24.4), or dipeptidylaminopeptidases. Phethiol alone significantly but partially protected endogenous (Met5) enkephalin released from depolarized brain slices, total protection being achieved when it was associated with an enkephalinase inhibitor. In order to obtain a parenterally-active inhibitor of cerebral aminopeptidases, the prodrug carbaphetiol, a readily hydrolyzable S-phenylcarbamoyl derivative of phethiol, was designed. Carbaphethiol (i.v.) elicited a rapid rise in mouse striatal level of Tyr-Gly-Gly, a characteristic extracellular metabolite of enkephalins. Carbapethiol alone and, even more, when associated with an enkephalinase inhibitor, exerted a potent naloxone-reversible antinociceptive activity. Carbaphethiol appears as the first parenterally-active inhibitor of cerebral aminopeptidases, potentially useful in neuropeptides degradation studies and as a pain-suppressing agent.
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PMID:Potent inhibition of cerebral aminopeptidases by carbaphethiol, a parenterally active compound. 324 26

The specificity of action of bovine brain cortex cathepsin D (EC 3.4.23.5) and high-Mr aspartic endopeptidase (EC 3.4.23.-) was studied with the vasoactive peptides renin substrate tetradecapeptide (RSTP), substance P (SP), and angiotensins I and II, and with model peptides--Lys-Pro-Ala-Glu-Phe-Phe (NO2)-Ala-Leu (I), Gly-Gly-His-Phe (NO2)-Phe-Ala-Leu-NH2 (II), and Abz-Ala-Ala-Phe-Phe-pNA (III). Cerebral aspartic peptidases show identical substrate specificity, cleaving the Leu10-Leu bond in RSTP and Phe-Phe in SP and peptide I-III, and not splitting angiotensins I and II. Because of the higher catalytic efficiency of cathepsin D (Kcat value), the specificity constants (Kcat/Km) for cathepsin D-catalyzed hydrolysis of substrates 1-111 are much higher than those for the high-Mr enzyme. High-Mr aspartic peptidase shares a number of properties with cathepsin D (sensitivity to pepstatin, substrate specificity, pH activity profile) and shows partial immunological identity; however, high-Mr aspartic peptidase has a specific activity 7-10 times lower than that of cathepsin D. The kinetic parameters of proteolysis of model peptides presented indicate that the high-Mr enzyme may be a complex of a single-chain cathepsin D with another polypeptide, although the possibility that it is an independent aspartic peptidase cannot be excluded.
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PMID:Substrate specificity of cerebral cathepsin D and high-Mr aspartic endopeptidase. 328 13


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