Electron transfer flavoprotein from pig liver mitochondria. A simple purification and re-evaluation of some of the molecular properties.
Electron transfer flavoprotein (ETF) from pig liver mitochondria has been purified to homogeneity by a three-step procedure with approx. 10-fold higher yields than previously reported. The purified ETF exhibits an absorption coefficient for the bound FAD of 13.5 mM-1.cm-1 at 436 nm and an isoelectric point of 6.75. Gel filtration, sodium dodecyl sulphate gel electrophoresis and flavin analysis indicate that pig liver ETF is a dimer, composed of non-identical subunits (Mr 38 000 and 32 000) with only one FAD/dimer. Anaerobic reduction by dithionite produces anionic flavin semiquinone as a stable intermediate and establishes the flavin to be the only redox-active chromophore in ETF.
D000596:Amino Acids / Q000032:analysis; D000818:Animals; D055598:Chemical Phenomena; D002621:Chemistry; D004227:Dithionite; D044927:Electron-Transferring Flavoproteins; D004591:Electrophoresis, Polyacrylamide Gel; D005420:Flavoproteins / Q000302:isolation & purification; D007525:Isoelectric Focusing; D046911:Macromolecular Substances; D008930:Mitochondria, Liver / Q000032:analysis*; D013053:Spectrophotometry; D013552:Swine
D000596:Amino Acids; D044927:Electron-Transferring Flavoproteins; D005420:Flavoproteins; D046911:Macromolecular Substances; D004227:Dithionite