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)

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.
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PMID:Analysis of the importance of arginine 102 in neutral endopeptidase (enkephalinase) catalysis. 137 21

The depressor, natriuretic and cyclic GMP responses to several species of brain natriuretic peptide (BNP) were compared to atrial natriuretic peptide (ANP) 99-126 in conscious spontaneously hypertensive rats (SHR) and in conscious cynomolgus monkeys treated with vehicle or the selective neutral endopeptidase (NEP 3.4.24.11) inhibitor N-[2-(mercaptomethyl)-1-oxo-3-phenylpropyl]-beta- alanine (SQ 28,603). In the conscious SHR, the natriuretic and cyclic GMP responses to 3 nmol/kg i.v. rat BNP-32 greater than rat ANP 99-126 greater than pig BNP-26 and were significantly potentiated by 100 mumol/kg i.v. SQ 28,603. Human BNP-32 was inactive in the SHR treated with either vehicle or SQ 28,603. In contrast, 1 nmol/kg i.v. of human BNP-32 stimulated renal and depressor responses in the conscious monkeys that were greater than or equal to those elicited by human ANP 99-126, whereas 3 nmol/kg i.v. rat BNP-32 reduced mean arterial pressure without affecting renal function. Furthermore, SQ 28,603 (100 mumol/kg, i.v.) significantly enhanced the cumulative losses of sodium and cyclic GMP stimulated by each of these peptides. In conclusion, the renal and depressor activities of BNP are highly species specific and are significantly potentiated by an inhibitor of NEP 3.4.24.11 in conscious SHR and monkeys. Therefore, protection of endogenous BNP may contribute importantly to the activity of NEP 3.4.24.11 inhibitors in cardiorenal disorders such as hypertension and congestive heart failure.
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PMID:Potentiation of brain natriuretic peptides by SQ 28,603, an inhibitor of neutral endopeptidase 3.4.24.11, in monkeys and rats. 138 30

We have characterized a T lymphocyte endopeptidase activity that hydrolyses succinyl-alanine-alanine-phenylalanine-paranitroanilide (Suc-Ala-Ala-Phe-pNa). Hydrolysis of this substrate by intact Jurkat T cells was markedly enhanced when exogenous aminopeptidase N was added to the incubation medium. It thus appears that the release of paranitroaniline from Suc-Ala-Ala-Phe-pNA results from the combination of two distinct enzymatic activities: (i) an endopeptidase activity that cleaves the substrate at the alanyl bond and (ii) an aminopeptidase activity that ultimately cleaves the phenylalanyl bond. This cleavage was further confirmed by HPLC analysis. Specific endopeptidase 24.11 inhibitors were shown to inhibit the endopeptidase activity. These features are reminiscent of the characteristics of neutral endopeptidase (NEP, also known as endopeptidase 24.11, CALLA or CD10). Anti-CD10 monoclonal antibodies (mAbs) recognized the CD10+ B cell line Raji, but not Jurkat cells as assessed by FACS analysis. This is probably due to a lack of sensitivity of this method, the level of NEP activity in Jurkat T cells being 3-5% of that measured in B cell lines. Anti-CD10 mAbs immunoprecipitated endopeptidase 24.11 activities in both Jurkat T cells and Raji B cells, demonstrating that T lymphocytes express a CALLA-related endopeptidase. We also demonstrate that T and B cell endopeptidases have the same molecular weight, that T cells express less functional CALLA mRNA than B cells and that there are at least two shorter transcripts (1.8 and 0.8 kb) in both T and B cells.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Jurkat T cells express a functional neutral endopeptidase activity (CALLA) involved in T cell activation. 139 81

Melanin-concentrating hormone (MCH) is a cyclic peptide which behaves as an antagonist of the pituitary melanotropic hormone alpha-melanocyte-stimulating hormone in fishes. Cloning of the rat MCH cDNA precursor recently revealed the presence of an additional putative peptide named NEI. The present work examined the susceptibility of these novel peptides to hydrolysis by various purified exo- and endo-peptidases including endopeptidases 24.11 (NEP), 24.15, 24.16, angiotensin-converting enzyme, leucine aminopeptidase and carboxypeptidase A. NEP attacked MCH at three sites of the molecule with an apparent affinity of about 12 microM and a kcat. of 4 min-1. The first site of cleavage was at Cys-7-Met-8, i.e. within the peptide loop formed by the internal disulphide bridge. NEP could therefore be considered as an MCH-inactivating peptidase since the degradation products generated are probably devoid of biological activity. In contrast, NEI neither inhibited the degradation of the NEP chromogenic substrate glutaryl-Phe-Ala-Phe-p-aminobenzoate nor was susceptible to proteolysis by NEP. Unlike NEP, angiotensin-converting enzyme, endopeptidase 24.15 and endopeptidase 24.16 appeared totally unable to cleave MCH, whereas the peptide was readily degraded by aminopeptidase M and carboxypeptidase A.
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PMID:Hydrolysis of rat melanin-concentrating hormone by endopeptidase 24.11 (neutral endopeptidase). 152 Feb 71

The plasmid pEAP31 contains the colicin E1 kil gene. Peptidoglycan and outer-membrane components (lipopoly-saccharide, proteins and phosphatidylethanolamine) decreased concurrently in the envelope fraction from Escherichia coli HB101 carrying pEAP31 during the stationary phase of growth. At almost the same time. D-alanine residues in peptidoglycan decreased. The Kil peptide is suggested to affect, directly or indirectly, the turnover of peptidoglycan in stationary phase and, as a result, to cause partial exfoliation of the outer membrane. Periplasmic proteins are liberated from E. coli HB101 (pEAP31) probably because of the exfoliation of outer membrane.
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PMID:Envelope alteration of Escherichia coli HB101 carrying pEAP31 caused by Kil peptide and its involvement in the extracellular release of periplasmic penicillinase from an alkaliphilic Bacillus. 190 20

Serum-free medium conditioned by the human hepatoma cell line HEP G2 was shown to contain a somatomedin-binding protein with a relative molecular mass of about 35,000. This binding protein was purified to homogeneity by the use of immunoaffinity chromatography and subsequent size exclusion chromatography. Antibodies for the immunoaffinity step were raised in rabbits against a previously isolated human amniotic fluid somatomedin-binding protein. The total composition and N-terminal amino acid sequence showed the protein to be identical to the binding protein from human amniotic fluid. Both have the N-terminal structure Ala-Pro-Trp-Gln-. The HEP G2 cell line offers a useful model to study the regulation of the synthesis and secretion of human somatomedin-binding proteins.
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PMID:The somatomedin-binding protein isolated from a human hepatoma cell line is identical to the human amniotic fluid somatomedin-binding protein. 240 14

Carbon-13 NMR spectroscopic studies of native and sequentially deglycosylated ovine submaxillary mucin (OSM) have been performed to examine the effects of glycosylation on the conformation and dynamics of the peptide core of O-linked glycoproteins. OSM is a large nonglobular glycoprotein in which nearly one-third of the amino acid residues are Ser and Thr which are glycosylated by the alpha-Neu-NAc(2-6)alpha-GalNAc- disaccharide. The beta-carbon resonances of glycosylated Ser and Thr residues in intact and asialo mucin display considerable chemical shift heterogeneity which, upon the complete removal of carbohydrate, coalesces to single sharp resonances. This chemical shift heterogeneity is due to peptide sequence variability and is proposed to reflect the presence of sequence-dependent conformations of the peptide core. These different conformations are thought to be determined by steric interactions of the GalNAc residue with adjacent peptide residues. The absence of chemical shift heterogeneity in apo mucin is taken to indicate a loss in the peptide-carbohydrate steric interactions, consistent with a more relaxed random coiled structure. On the basis of the 13C relaxation behavior (T1 and NOE) the dynamics of the alpha-carbons appear to be unique to each amino acid type and glycosylation state, with alpha-carbon mobilities decreasing in the order Gly greater than Ala = Ser greater than Thr much greater than monoglycosylated Ser/Thr approximately greater than disaccharide linked Ser/Thr.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effects of glycosylation on the conformation and dynamics of O-linked glycoproteins: carbon-13 NMR studies of ovine submaxillary mucin. 277 22

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

A gene coding for the Tac protein (interleukin-2 receptor alpha-subunit, IL-2R alpha) of the interleukin-2 receptor was constructed by chemoenzymatic gene synthesis. The gene designed for mutagenesis codes for a receptor protein where all 10 methionines are substituted by alanine, valine, leucine, and isoleucine. In addition, aspartate at position 6 is substituted by glutamate. This desmethionine IL-2R alpha and the wild-type IL-2R alpha genes were integrated into a eukaryotic expression vector and transferred into different cell lines. The recipient cell lines express both wild-type and mutant receptor proteins on their cell surfaces which are recognized equally by different monoclonal antibodies. It was possible to establish cell lines with high level IL-2R alpha chain expression by fluorescence-activated cell sorting. The wild-type IL-2R alpha expressed in LTK- cells is a glycoprotein with an apparent molecular size of about 60 kDa and a typical low interleukin-2 binding affinity of KD = 12 nM. Despite the fact that 11 amino acids are altered, no significant difference in the mutant IL-2R alpha is observed, exhibiting the same molecular size and a low interleukin-2 binding affinity of KD = 26 nM.
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PMID:Expression and characterization of a des-methionine mutant interleukin-2 receptor (Tac protein) with interleukin-2 binding affinity. 313 42

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


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