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Search Results: 1 - 10 of 931566 matches for " Fran?a M.S.F. "
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Partial sequence and toxic effects of granulitoxin, a neurotoxic peptide from the sea anemone Bunodosoma granulifera
Santana A.N.C.,Leite A.B.,Frana M.S.F.,Frana L.
Brazilian Journal of Medical and Biological Research , 1998,
Abstract: A neurotoxic peptide, granulitoxin (GRX), was isolated from the sea anemone Bunodosoma granulifera. The N-terminal amino acid sequence of GRX is AKTGILDSDGPTVAGNSLSGT and its molecular mass is 4958 Da by electrospray mass spectrometry. This sequence presents a partial degree of homology with other toxins from sea anemones such as Bunodosoma caissarum, Anthopleura fuscoviridis and Anemonia sulcata. However, important differences were found: the first six amino acids of the sequence are different, Arg-14 was replaced by Ala and no cysteine residues were present in the partial sequence, while two cysteine residues were present in the first 21 amino acids of other toxins described above. Purified GRX injected ip (800 μg/kg) into mice produced severe neurotoxic effects such as circular movements, aggressive behavior, dyspnea, tonic-clonic convulsion and death. The 2-h LD50 of GRX was 400 ± 83 μg/kg.
A new brain metalloendopeptidase which degrades the Alzheimer ?-amyloid 1-40 peptide producing soluble fragments without neurotoxic effects
Carvalho, K.M.;Frana, M.S.F.;Camar?o, G.C.;Ruchon, A.F.;
Brazilian Journal of Medical and Biological Research , 1997, DOI: 10.1590/S0100-879X1997001000002
Abstract: a new metalloendopeptidase was purified to apparent homogeneity from a homogenate of normal human brain using successive steps of chromatography on deae-trisacryl, hydroxylapatite and sephacryl s-200. the purified enzyme cleaved the gly33-leu34 bond of the 25-35 neurotoxic sequence of the alzheimer ?-amyloid 1-40 peptide producing soluble fragments without neurotoxic effects. this enzyme activity was only inhibited by divalent cation chelators such as edta, egta and o-phenanthroline (1 mm) and was insensitive to phosphoramidon and captopril (1 μm concentration), specific inhibitors of neutral endopeptidase (ec 3.4.24.11) and angiotensin-converting enzyme (ec 3.4.15.1), respectively. the high affinity of this human brain endopeptidase for ?-amyloid 1-40 peptide (km = 5 μm) suggests that it may play a physiological role in the degradation of this substance produced by normal cellular metabolism. it may also be hypothesized that the abnormal accumulation of the amyloid ?-protein in alzheimer's disease may be initiated by a defect or an inactivation of this enzyme.
A new brain metalloendopeptidase which degrades the Alzheimer -amyloid 1-40 peptide producing soluble fragments without neurotoxic effects
Carvalho K.M.,Frana M.S.F.,Camar?o G.C.,Ruchon A.F.
Brazilian Journal of Medical and Biological Research , 1997,
Abstract: A new metalloendopeptidase was purified to apparent homogeneity from a homogenate of normal human brain using successive steps of chromatography on DEAE-Trisacryl, hydroxylapatite and Sephacryl S-200. The purified enzyme cleaved the Gly33-Leu34 bond of the 25-35 neurotoxic sequence of the Alzheimer -amyloid 1-40 peptide producing soluble fragments without neurotoxic effects. This enzyme activity was only inhibited by divalent cation chelators such as EDTA, EGTA and o-phenanthroline (1 mM) and was insensitive to phosphoramidon and captopril (1 μM concentration), specific inhibitors of neutral endopeptidase (EC 3.4.24.11) and angiotensin-converting enzyme (EC 3.4.15.1), respectively. The high affinity of this human brain endopeptidase for -amyloid 1-40 peptide (Km = 5 μM) suggests that it may play a physiological role in the degradation of this substance produced by normal cellular metabolism. It may also be hypothesized that the abnormal accumulation of the amyloid -protein in Alzheimer's disease may be initiated by a defect or an inactivation of this enzyme.
Specific fluorogenic substrates for neprilysin (neutral endopeptidase, EC 3.4.24.11) which are highly resistant to serine- and metalloproteases
Medeiros M.A.S.,Frana M.S.F.,Boileau G.,Juliano L.
Brazilian Journal of Medical and Biological Research , 1997,
Abstract: Two intramolecularly quenched fluorogenic peptides containing o-aminobenzoyl (Abz) and ethylenediamine 2,4-dinitrophenyl (EDDnp) groups at amino- and carboxyl-terminal amino acid residues, Abz-DArg-Arg-Leu-EDDnp (Abz-DRRL-EDDnp) and Abz-DArg-Arg-Phe-EDDnp (Abz-DRRF-EDDnp), were selectively hydrolyzed by neutral endopeptidase (NEP, enkephalinase, neprilysin, EC 3.4.24.11) at the Arg-Leu and Arg-Phe bonds, respectively. The kinetic parameters for the NEP-catalyzed hydrolysis of Abz-DRRL-EDDnp and Abz-DRRF-EDDnp were Km = 2.8 μM, kcat = 5.3 min-1, kcat/Km = 2 min-1 μM-1 and Km = 5.0 μM, kcat = 7.0 min-1, kcat/Km = 1.4 min-1 μM-1, respectively. The high specificity of these substrates was demonstrated by their resistance to hydrolysis by metalloproteases [thermolysin (EC 3.4.24.2), angiotensin-converting enzyme (ACE; EC 3.4.24.15)], serineproteases [trypsin (EC 3.4.21.4), a-chymotrypsin (EC 3.4.21.1)] and proteases present in tissue homogenates from kidney, lung, brain and testis. The blocked amino- and carboxyl-terminal amino acids protected these substrates against the action of aminopeptidases, carboxypeptidases and ACE. Furthermore, DR amino acids ensured total protection of Abz-DRRL-EDDnp and Abz-DRRF-EDDnp against the action of thermolysin and trypsin. Leu-EDDnp and Phe-EDDnp were resistant to hydrolysis by a-chymotrypsin. The high specifity of these substrates suggests their use for specific NEP assays in crude enzyme preparations
A liver metalloendopeptidase which degrades the circulating hypotensive peptide hormones bradykinin and atrial natriuretic peptide
Carvalho, K.M.;Nava, R.A.;Frana, M.S.F.;Medeiros, M.A.S.;Camar?o, G.C.;Juliano, L.;
Brazilian Journal of Medical and Biological Research , 1999, DOI: 10.1590/S0100-879X1999000100007
Abstract: a new metalloendopeptidase was purified to apparent homogeneity from a homogenate of normal human liver using successive steps of chromatography on deae-cellulose, hydroxyapatite and sephacryl s-200. the purified enzyme hydrolyzed the pro7-phe8 bond of bradykinin and the ser25-tyr26 bond of atrial natriuretic peptide. no cleavage was produced in other peptide hormones such as vasopressin, oxytocin or met- and leu-enkephalin. this enzyme activity was inhibited by 1 mm divalent cation chelators such as edta, egta and o-phenanthroline and was insensitive to 1 μm phosphoramidon and captopril, specific inhibitors of neutral endopeptidase (ec 3.4.24.11) and angiotensin-converting enzyme (ec 3.4.15.1), respectively. with mr 85 kda, the enzyme exhibits optimal activity at ph 7.5. the high affinity of this endopeptidase for bradykinin (km = 10 μm) and for atrial natriuretic peptide (km = 5 μm) suggests that it may play a physiological role in the inactivation of these circulating hypotensive peptide hormones.
A liver metalloendopeptidase which degrades the circulating hypotensive peptide hormones bradykinin and atrial natriuretic peptide
Carvalho K.M.,Nava R.A.,Frana M.S.F.,Medeiros M.A.S.
Brazilian Journal of Medical and Biological Research , 1999,
Abstract: A new metalloendopeptidase was purified to apparent homogeneity from a homogenate of normal human liver using successive steps of chromatography on DEAE-cellulose, hydroxyapatite and Sephacryl S-200. The purified enzyme hydrolyzed the Pro7-Phe8 bond of bradykinin and the Ser25-Tyr26 bond of atrial natriuretic peptide. No cleavage was produced in other peptide hormones such as vasopressin, oxytocin or Met- and Leu-enkephalin. This enzyme activity was inhibited by 1 mM divalent cation chelators such as EDTA, EGTA and o-phenanthroline and was insensitive to 1 μM phosphoramidon and captopril, specific inhibitors of neutral endopeptidase (EC 3.4.24.11) and angiotensin-converting enzyme (EC 3.4.15.1), respectively. With Mr 85 kDa, the enzyme exhibits optimal activity at pH 7.5. The high affinity of this endopeptidase for bradykinin (Km = 10 μM) and for atrial natriuretic peptide (Km = 5 μM) suggests that it may play a physiological role in the inactivation of these circulating hypotensive peptide hormones.
Specific fluorogenic substrates for neprilysin (neutral endopeptidase, EC 3.4.24.11) which are highly resistant to serine- and metalloproteases
Medeiros, M.A.S.;Frana, M.S.F.;Boileau, G.;Juliano, L.;Carvalho, K.M.;
Brazilian Journal of Medical and Biological Research , 1997, DOI: 10.1590/S0100-879X1997001000003
Abstract: two intramolecularly quenched fluorogenic peptides containing o-aminobenzoyl (abz) and ethylenediamine 2,4-dinitrophenyl (eddnp) groups at amino- and carboxyl-terminal amino acid residues, abz- $mvd$:face("times") darg-arg-leu-eddnp (abz- $mvd$:face("times") drrl-eddnp) and abz- $mvd$:face("times") darg-arg-phe-eddnp (abz- $mvd$:face("times") drrf-eddnp), were selectively hydrolyzed by neutral endopeptidase (nep, enkephalinase, neprilysin, ec 3.4.24.11) at the arg-leu and arg-phe bonds, respectively. the kinetic parameters for the nep-catalyzed hydrolysis of abz- $mvd$:face("times") drrl-eddnp and abz- $mvd$:face("times") drrf-eddnp were km = 2.8 μm, kcat = 5.3 min-1, kcat/km = 2 min-1 μm-1 and km = 5.0 μm, kcat = 7.0 min-1, kcat/km = 1.4 min-1 μm-1, respectively. the high specificity of these substrates was demonstrated by their resistance to hydrolysis by metalloproteases [thermolysin (ec 3.4.24.2), angiotensin-converting enzyme (ace; ec 3.4.24.15)], serineproteases [trypsin (ec 3.4.21.4), $mvd$:face("symbol") a-chymotrypsin (ec 3.4.21.1)] and proteases present in tissue homogenates from kidney, lung, brain and testis. the blocked amino- and carboxyl-terminal amino acids protected these substrates against the action of aminopeptidases, carboxypeptidases and ace. furthermore, $mvd$:face("times") dr amino acids ensured total protection of abz- $mvd$:face("times") drrl-eddnp and abz- $mvd$:face("times") drrf-eddnp against the action of thermolysin and trypsin. leu-eddnp and phe-eddnp were resistant to hydrolysis by $mvd$:face("symbol") a-chymotrypsin. the high specifity of these substrates suggests their use for specific nep assays in crude enzyme preparations
Partial sequence and toxic effects of granulitoxin, a neurotoxic peptide from the sea anemone Bunodosoma granulifera
Santana, A.N.C.;Leite, A.B.;Frana, M.S.F.;Frana, L.;Vale, O.C.;Cunha, R.B.;Ricart, C.A.O.;Sousa, M.V.;Carvalho, K.M.;
Brazilian Journal of Medical and Biological Research , 1998, DOI: 10.1590/S0100-879X1998001000015
Abstract: a neurotoxic peptide, granulitoxin (grx), was isolated from the sea anemone bunodosoma granulifera. the n-terminal amino acid sequence of grx is aktgildsdgptvagnslsgt and its molecular mass is 4958 da by electrospray mass spectrometry. this sequence presents a partial degree of homology with other toxins from sea anemones such as bunodosoma caissarum, anthopleura fuscoviridis and anemonia sulcata. however, important differences were found: the first six amino acids of the sequence are different, arg-14 was replaced by ala and no cysteine residues were present in the partial sequence, while two cysteine residues were present in the first 21 amino acids of other toxins described above. purified grx injected ip (800 μg/kg) into mice produced severe neurotoxic effects such as circular movements, aggressive behavior, dyspnea, tonic-clonic convulsion and death. the 2-h ld50 of grx was 400 ± 83 μg/kg.
Foliar flavonoids of nine species of Bauhinia
SALATINO, ANTONIO;BLATT, CECíLIA T.T.;SANTOS, DéBORAH Y.A.C. DOS;VAZ, ANGELA M.S.F.;
Brazilian Journal of Botany , 1999, DOI: 10.1590/S0100-84041999000100003
Abstract: foliar flavonoids of nine species of bauhinia were isolated and identified. all the compounds correspond to glycosides derived from kaempferol, quercetin, isorhamnetin and myricetin. derivatives of the latter aglyconhe seem to be rare in bauhinia. derivatives of isorhamnetin are commonly found in species of subgenus bauhinia and were not detected in the two species of subgenus phanera. flavonoid patterns of species of the former subgenus are in general more complex than those of the latter.
Foliar flavonoids of nine species of Bauhinia
SALATINO ANTONIO,BLATT CECíLIA T.T.,SANTOS DéBORAH Y.A.C. DOS,VAZ ANGELA M.S.F.
Brazilian Journal of Botany , 1999,
Abstract: Foliar flavonoids of nine species of Bauhinia were isolated and identified. All the compounds correspond to glycosides derived from kaempferol, quercetin, isorhamnetin and myricetin. Derivatives of the latter aglyconhe seem to be rare in Bauhinia. Derivatives of isorhamnetin are commonly found in species of subgenus Bauhinia and were not detected in the two species of subgenus Phanera. Flavonoid patterns of species of the former subgenus are in general more complex than those of the latter.
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