Erythrocyte glucose-6-phosphate dehydrogenase activity assay and affinity for its substrate under "physiological" conditions
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 availability is poor.
| Main Authors: | , |
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| Format: | Digital revista |
| Language: | English |
| Published: |
Associação Brasileira de Divulgação Científica
1998
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| Online Access: | http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X1998001200004 |
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