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| Barretto,O.C. de O.; Oshiro,M.; Oliveira,R.A.G.; Fedullo,J.D.L.; Nonoyama,K.. |
| In a comparative study of erythrocyte metabolism of vertebrates, the specific activity of glucose-6-phosphate dehydrogenase (G6PD) of the Brazilian opossum Didelphis marsupialis in a hemolysate was shown to be high, 207 ± 38 IU g-1 Hb-1 min-1 at 37ºC, compared to the human erythrocyte activity of 12 ± 2 IU g-1 Hb-1 min-1 at 37ºC. The apparent high specific activity of the mixture led us to investigate the physicochemical properties of the opossum enzyme. We report that reduced glutathione (GSH) in the erythrocytes was only 50% higher than in human erythrocytes, a value lower than expected from the high G6PD activity since GSH is maintained in a reduced state by G6PD activity. The molecular mass, determined by G-200 Sephadex column chromatography at pH 8.0,... |
| Tipo: Info:eu-repo/semantics/other |
Palavras-chave: Erythrocyte glucose-6-phosphate dehydrogenase; Didelphis marsupialis; Erythrocyte glutathione. |
| Ano: 2006 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2006000500007 |
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| Leite,A.A.; Barretto,O.C. de O.. |
| Glucose-6-phosphate dehydrogenase (G6PD) activity and the affinity for its substrate glucose-6-phosphate were investigated under conditions similar to the physiological environment in terms of ionic strength (I: 0.188), cation concentration, pH 7.34, and temperature (37oC). A 12.4, 10.4 and 21.4% decrease was observed in G6PD B, G6PD A+ and G6PD A- activities, respectively. A Km increase of 95.1, 94.4 and 95.4% was observed in G6PD B, G6PD A+ and G6PD A-, respectively, leading to a marked decrease in affinity. In conclusion, the observation of the reduced activity and affinity for its natural substrate reflects the actual pentose pathway rate. It also suggests a much lower NADPH generation, which is crucial mostly in G6PD-deficient individuals, whose NADPH... |
| Tipo: Info:eu-repo/semantics/other |
Palavras-chave: Glucose-6-phosphate dehydrogenase; Red blood cells; G6PD activity and affinity. |
| Ano: 1998 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X1998001200004 |
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| Guerra-Shinohara,E.M.; Barretto,O.C. de O.. |
| Erythrocyte membrane proteins from 44 representative mammals were studied. Protein 4.2 was not detected in guinea pigs (Cavia porcellus) (N = 14), Southern Brazilian swamp large rats (Myocastor coypus) (N = 2), cutias (Dasyprocta sp) (N = 4), and horses (Equus caballus) (N = 13). These animals also presented high ankyrin concentrations except for the horse which did not exhibit a sharp band, although minor components located between proteins 2 and 3 could account for the ankyrin family. The rodents studied did present band 6, which was not detectable in other common rodents such as white rats (Rattus norvegicus) (N = 9) and mice (Mus musculus) (N = 12). Since the absence of protein 4.2 does not disrupt the cytoskeleton membrane, we suggest that it is not... |
| Tipo: Info:eu-repo/semantics/other |
Palavras-chave: Protein 4.2; Erythrocyte membrane cytoskeleton; Mammals. |
| Ano: 1999 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X1999000600003 |
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| Barretto,O.C. de O.; Satake,M.; Nonoyama,K.; Cardoso,J.L.C.. |
| Eighty micrograms red blood cell (RBC) ghosts from patients who had previously exhibited the cutaneous form of loxoscelism (presenting localized dermonecrosis) and the viscerocutaneous form of loxoscelism (presenting dermonecrosis, hemoglobinuria, hematuria, and jaundice) and from controls were incubated with 2.5 µg crude Loxosceles gaucho venom in 5 mM phosphate buffer, pH 7.4, at 37ºC. Among all membrane proteins, quantitative proteolysis of the important integral transmembrane protein 3 increased with venom dose and with incubation time from 30 to 120 min, as demonstrated by gel densitometry. Similar quantitative data were obtained for RBC ghosts from patients and from control subjects, a fact that argues against the possibility of genetic factors... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Loxoscelism; Loxosceles sp; Spider venom; Red blood cell membrane protein 3. |
| Ano: 2003 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2003000300004 |
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