title: 1-Methyl-4-phenyl-pyridinium-induced inhibition of nicotinamide adenosine dinucleotide cytochrome c reductase.
abstract: The effect of 1-methyl-4-phenyl-pyridinium (MPP+), the main toxic metabolite of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), a parkinsonism-causing neurotoxin, upon the activity of nicotinamide adenine dinucleotide (NADH) cytochrome c reductase (EC 1.6.99.3) and upon that of glutathione reductase (EC 1.6.4.2) was monitored spectrophotometrically. For the cytochrome c reductase, the increase in absorbance of reduced cytochrome c was measured at 550 nm; for evaluating glutathione reductase, the absorbance of nicotinamide adenine dinucleotide phosphate (NADPH) was followed at 340 nm. MPP+ but not MPTP reversibly inhibited NADH cytochrome c reductase, but not glutathione reductase. This may be a direct mechanism of cell toxicity by this neurotoxin.
mesh_terms: D015632:1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; D015655:1-Methyl-4-phenylpyridinium; D000818:Animals; D003579:Cytochrome Reductases / Q000037:antagonists & inhibitors*; D005980:Glutathione Reductase / Q000378:metabolism; D009245:NADH Dehydrogenase / Q000037:antagonists & inhibitors*; D010302:Parkinson Disease, Secondary / Q000139:chemically induced; D011725:Pyridines / Q000378:metabolism / Q000494:pharmacology; D011726:Pyridinium Compounds / Q000378:metabolism / Q000494:pharmacology*; D013053:Spectrophotometry
chemical_list: D011725:Pyridines; D011726:Pyridinium Compounds; D015632:1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; D003579:Cytochrome Reductases; D009245:NADH Dehydrogenase; D005980:Glutathione Reductase; D015655:1-Methyl-4-phenylpyridinium