title: High activity of alpha-glycerophosphate oxidation by human placental mitochondria.
abstract: Human term placental mitochondria oxidize alpha-glycerophosphate at an unusually high rate as compared to other substrates. The apparent Km both for oxidation and alpha-glycerophosphate dehydrogenase (EC 1.1.99.5) activity of DL-alpha glycerophosphate determined in a medium containing 2mM EDTA and 5 mM MgSO4 was approx. 0.7 mM. EDTA inhibited the alpha-glycerophosphate oxidation if the later was used at low concentrations. A subsequent addition of MgSO4 or CaCl2 restored the original activity. EDTA had no effect on mitochondrial respiration at high concentration of alpha-glycerophosphate. Possible physiological role of relatively high activity of human placental mitochondrial alpha-glycerophosphate dehydrogenase is discussed.
mesh_terms: D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone / Q000494:pharmacology; D004492:Edetic Acid / Q000494:pharmacology; D005260:Female; D005993:Glycerolphosphate Dehydrogenase / Q000378:metabolism; D005994:Glycerophosphates / Q000378:metabolism*; D006801:Humans; D007700:Kinetics; D008274:Magnesium / Q000494:pharmacology; D008854:Microscopy, Electron; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D010101:Oxygen Consumption / Q000187:drug effects; D010920:Placenta / Q000378:metabolism*; D011247:Pregnancy
chemical_list: D005994:Glycerophosphates; D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone; D004492:Edetic Acid; D005993:Glycerolphosphate Dehydrogenase; D008274:Magnesium