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

Fast atom bombardment mass spectrometry (FAB-MS) and high-performance liquid chromatography using a photodiode-array ultraviolet detector were applied to study a dynorphin-converting endopeptidase from the human pituitary gland. The specificity of the enzyme was tested towards various opioid peptides derived from the prodynorphin precursor, i.e. dynorphin A, dynorphin B and alpha-neoendorphin. Peptide fragments were analysed directly by continuous-flow FAB-MS and those containing aromatic amino acids were detected independently by the photodiode-array ultraviolet detector. The results obtained suggest a similar processing of these structure-related substrates and it appears that the enzyme recognizes the dibasic stretch in their sequence. It is also clear from this study that the combination of the above techniques provides a powerful tool for studies of enzymatic conversion among the prodynorphin-derived peptides and it should be applicable to studies of similar mechanisms in other peptide systems.
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PMID:Approach to studying proteinase specificity by continuous-flow fast atom bombardment mass spectrometry and high-performance liquid chromatography combined with photodiode-array ultraviolet detection. 168 13

Endopeptidase 24.15, a metalloendopeptidase active in brain, rapidly converts prodynorphin-derived peptides into leu-enkephalin. Inhibitors of this enzyme slow the degradation of these peptides in vivo and in vitro. The present study evaluated two inhibitors of endopeptidase 24.15, N-[1-(RS)-carboxy-3-phenyl-propyl]-Ala-Ala-Phe-p-aminobenzoate (cFP-AAF-pAB), and N-[1-(RS)-carboxy-3-phenylpropyl]-Ala-D-Ala-Phe-p-aminobenzoate (cFP-A(D)AF-pAB), for antinociception on the tail-flick and jump tests in rats following intracerebroventricular administration relative to an inhibitor of endopeptidase 24.11, N-(1-(RS)-carboxy-3-phenylpropyl]-Phe-p-aminobenzoate (cFP-F-pAB). cFP-AAF-pAB, cFP-A(D)AF-pAB and cFP-F-pAB produced equipotent dose-dependent (25-250 nmol) and time-dependent (5-7 h) antinociception with larger effects on the jump (49-51% increase) relative to the tail-flick (28-41% increase) test. Naloxone (1 mg/kg, SC) significantly reduced antinociception elicited by all inhibitors on the jump test. Motor performance failed to be affected by inhibitor administration. The gradual appearance of antinociception and its naloxone sensitivity suggest that these effects are mediated through inhibition of opioid peptide degradation.
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PMID:Antinociceptive properties of inhibitors of endopeptidase 24.15. 193 29

An endopeptidase that converts the opioid peptide dynorphin B (Tyr-Gly-Gly-Phe-Leu-Arg-aRg-Gln-Phe-Lys-Val-Val-Thr) to its bioactive fragment Leu-enkephalin-Arg6 was isolated from bovine spinal cord. The enzyme was purified about 230-fold from a concentrated spinal cord extract. Upon sodium dodecyl sulfate-polyacrylamide gel electrophoresis, it stained as a protein of Mr 55,000. The purified enzyme is optimally active at around pH7 and has essential thiol groups. It appears to be highly specific for dynorphin B (Km = 11 microM) but not for alpha-neoendorphin or dynorphin A, two other opioids included in the prodynorphin precursor. From its specificity, molecular size, and inhibitory spectrum, this enzyme is different from other known dynorphin-converting or -degrading enzymes and appears to be a unique and novel endoprotease.
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PMID:A novel bovine spinal cord endoprotease with high specificity for dynorphin B. 256 32

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

A secreted dibasic cleaving peptidase capable of converting dynorphins into Leu-enkephalin-Arg6 was purified from the medium of EL-4 mouse thymoma cells. The enzyme is a novel metalloendopeptidase with a neutral pH optimum (6.9) and a molecular weight of approximately 130 000. The dibasic cleaving enzyme was completely inhibited in the presence of 20-50 mM amine buffers, 0.1 mM EDTA, 0.5 mM 1,10-phenanthroline, 0.5 mM N-ethylmaleimide, and 1mM DTNB. Unlike the Kex2 family of proteases, Ca2+ did not activate the endopeptidase, but high concentrations (1 mM) of metal ions such as Cu2+, Ni2+, Zn2+, and Co2+ completely inhibited the enzyme. Inhibition was not seen with 0.2 mM TLCK, 1 mM DTT, and 1 mM PMSF. The enzyme will cleave Arg-Arg and Arg-Lys bonds, but not Lys-Arg or Lys-Lys bonds in identical environments, and no aminopeptidase or carboxypeptidase activity was seen. The size of the substrate does not seem to be a determining factor, since dynorphin A(1-12) is cleaved at a rate similar to prodynorphin B(228-256) containing 29 amino acids. The identity of the residues on either side of the cleavage site influences the rate of processing, as noted by different rates of cleavage for the same size peptides dynorphin A(1-13) vs dynorphin A(1-9) vs beta-neoendorphin. The presence of proline in the P3' (alpha-neoendorphin), P4' (dynorphin A(1-11)), or P5' (bovine adrenal medulla dodecapeptide) position does not prevent cleavage, but neurotensin and its (1-11) fragment containing both P2 and P2' proline residues are not cleaved.
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PMID:Purification and characterization of a secreted arginine-specific dibasic cleaving enzyme from EL-4 cells. 754 86

N-[1(R,S)-Carboxy-3-phenylpropyl]-Ala-Ala-Phe-p-aminobenzoate (cFP-AAF-pAB) is a potent, substrate-related, specific inhibitor of endopeptidase 24.15, an enzyme involved in the metabolism of bioactive peptides including bradykinin, neurotensin, and proenkephalin, and prodynorphin-derived enkephalin precursors. The observation that this inhibitor causes a pronounced decrease in blood pressure after intravenous infusion into normotensive rats posed the question of the mechanism of this hypotensive response. It was suggested previously that cFP-AAF-pAB is an inhibitor of angiotensin converting enzyme (ACE) and that this function can account for the hypotensive response to the inhibitor. We present here evidence that cFP-AAF-pAB has no intrinsic ACE-inhibitory activity. The previously observed inhibition is shown to be dependent on cleavage of the Ala-Phe bond in the inhibitor by endopeptidase 24.11 (enkephalinase, EC 3.4.24.11), a contaminant of some ACE preparations.
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PMID:Evidence that enzymatic conversion of N-[1(R,S)-carboxy-3-phenylpropyl]-Ala-Ala-Phe-p-aminobenzoate, a specific inhibitor of endopeptidase 24.15, to N-[1(R,S)-carboxy-3-phenylpropyl]-Ala-Ala is necessary for inhibition of angiotensin converting enzyme. 813 8

Prodynorphin is post-translationally processed into dynorphin B-13 and other peptides by the action of endopeptidases that cleave at pairs of basic amino acids and at single basic residues, followed by a carboxypeptidase that removes the C-terminal basic residues. To evaluate the specificity of neuropeptide processing enzymes, rat prodynorphin was transfected into BRL-3A cells, a rat liver-derived cell line which produces insulin-like growth factor II, but does not normally express prodynorphin. The transfected prodynorphin was post-translationally processed at both monobasic and dibasic cleavage sites, with the formation of dynorphin B-13 and other peptides. This finding indicates that BRL-3A cells express prodynorphin-processing enzymes. These cells were found to secrete two enzyme activities previously implicated in the processing of dynorphin, a monobasic cleaving 'dynorphin converting enzyme' and 'carboxypeptidase E', based on inhibitor sensitivities and pH optima. The dynorphin converting enzyme secreted from BRL-3A cells elutes from an anion exchange column under the same conditions as the enzyme secreted from pituitary-derived cell lines (AtT-20, GH4C1). Northern blot analysis indicates that BRL-3A cells express carboxypeptidase E mRNA in addition to mRNA encoding furin, a prohormone-processing endopeptidase. The mRNAs for two other related endopeptidases, prohormone convertase 1 and 2, were not detected on Northern blots, suggesting that these enzymes are not required for the processing of prodynorphin. The expression of carboxypeptidase E, furin, and dynorphin converting enzyme in BRL-3A cells suggests that these peptide processing enzymes are not specific for neuropeptides, but are also present in cells which process peptide growth factors.
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PMID:Processing of prodynorphin in BRL-3A cells, a rat liver-derived cell line: implications for the specificity of neuropeptide-processing enzymes. 837 74

Invertebrate tissues contain mammalian-like proenkephalin, prodynorphin, and proopiomelanocortin. Amino acid sequence determination of these opioid gene products reveals the presence of various opioid peptides exhibiting high sequence identity with their mammalian counterparts. These associated peptides are flanked by dibasic amino acid residues, indicating cleavage sites. Together with the presence of various processing enzymes, i.e., neutral endopeptidase 24.11 and angiotensin-converting enzymes, this suggests that opioid precursor processing is also similar to that described in mammals. It is noted that the levels and/or activity of invertebrate neutral endopeptidase 24.11 can be upregulated by signaling molecules shown to perform the same function in mammals, i.e., morphine. Critical to opioid precursor processing are immunocytes that contain the precursors and transport processing enzymes to sites of inflammation, in part, to cleave these peptide precursors, thus liberating immune-stimulating molecules. Furthermore, in response to lipopolysaccharides, Met-enkephalin levels peak immediately and hours after the exposure, revealing a release and induction process. It appears that the opioid precursors and their processing enzymes first evolved in "simple" animals and the have been maintained and embellished during the course of evolution guided by conformational matching.
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PMID:Invertebrate opioid precursors: evolutionary conservation and the significance of enzymatic processing. 1021 82

Endothelin-converting enzyme-2 (ECE-2), a member of M13 family of zinc metallopeptidases, has previously been shown to process a number of neuropeptides including those derived from prodynorphin, proenkephalin, proSAAS, and amyloid precursor protein. ECE-2, unlike ECE-1, exhibits restricted neuroendocrine distribution and acidic pH optimum; it is consistent with a role in the regulation of neuropeptide levels in vivo. Here, we report the generation of a three-dimensional (3D) molecular model of ECE-2 using the crystal structure of neprilysin (EC 3.4.24.11) as a template. On the basis of the predictions made from the molecular model, we mutated and tested two residues, Trp 148 and Tyr 563, in the catalytic site. The mutation of Tyr 563 was found to significantly affect the catalytic activity and inhibitor binding. The molecular model was used to virtually screen a small molecule library of 13 000 compounds. Among the top-scoring compounds three were found to inhibit ECE-2 with high affinity and exhibited specificity for ECE-2 compared to neprilysin. Thus, the model provides a new useful tool to probe the active site of ECE-2 and design additional selective inhibitors of this enzyme.
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PMID:Homology modeling and site-directed mutagenesis to identify selective inhibitors of endothelin-converting enzyme-2. 1850 70