title: Stimulation of glyceraldehyde-3-phosphate dehydrogenase by oxyhemoglobin.
abstract: Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is a key glycolytic enzyme regulated by many diverse mechanisms. In this study we present evidence that GAPDH activity is stimulated in the presence of oxyhemoglobin (2.3-fold, P < 0.005). No stimulation was seen by myoglobin, and only slight stimulation (1.2-fold, not significant) by methemoglobin was observed. Such stimulation may have physiological significance as 1,3-bis-phosphoglycerate, the product of GAPDH, isomerises to 2,3-bis-phosphoglycerate, an allosteric effector that decreases the oxygen affinity of hemoglobin, thus providing a feedback loop. The results suggest that when assaying GAPDH activity in biological samples, hemoglobin content should be taken into account.
authors.affiliation: Department of Neurochemistry, Institute of Neurology, London, UK. pbrookes@ion.ucl.ac.uk
authors.forename: P S
authors.initials: PS
authors.lastname: Brookes
authors.forename: J M
authors.initials: JM
authors.lastname: Land
authors.forename: J B
authors.initials: JB
authors.lastname: Clark
authors.forename: S J
authors.initials: SJ
authors.lastname: Heales
mesh_terms: D000818:Animals; D004789:Enzyme Activation; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases / Q000378:metabolism*; D008099:Liver / Q000201:enzymology; D051379:Mice; D008810:Mice, Inbred C57BL; D008808:Mice, Inbred CBA; D010108:Oxyhemoglobins / Q000494:pharmacology*
chemical_list: D010108:Oxyhemoglobins; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases