Partial purification and properties of the external NADH dehydrogenase from cuckoo-pint (Arum maculatum) mitochondria.
The external NADH dehydrogenase has been purified from Arum maculatum (cuckoo-pint) mitochondria by phosphate washing, extraction with deoxycholate, ion-exchange and gel-filtration chromatography. Sodium dodecyl sulphate/polyacrylamide-gel electrophoresis shows, when the gel is silver-stained, that the purified enzyme contains two major bands of Mr 78 000 and 65 000 and a minor one of Mr about 76 000. It is not possible at present to determine which of these, or which combination, constitutes the dehydrogenase. The enzyme contains non-covalently bound FAD and a small amount of FMN. Since the conditions of purification lead to considerable loss of flavin and possibly iron-sulphur centres, it is not possible to decide with certainty whether the enzyme is a flavo- or ferroflavo-protein. The enzyme has been distinguished from the other NADH dehydrogenases on the basis of its substrate specificity, its capability of reducing electron acceptors such as ubiquinone-1 and 2,6-dichlorophenol-indophenol and its sensitivity towards Ca2+, EGTA and dicoumarol.
D002850:Chromatography, Gel; D002852:Chromatography, Ion Exchange; D003579:Cytochrome Reductases / Q000378:metabolism*; D003840:Deoxycholic Acid; D005415:Flavins / Q000032:analysis; D005615:Freezing; D008928:Mitochondria / Q000201:enzymology; D009245:NADH Dehydrogenase / Q000037:antagonists & inhibitors / Q000302:isolation & purification / Q000378:metabolism*; D010446:Peptide Fragments / Q000032:analysis; D010944:Plants / Q000201:enzymology*; D013379:Substrate Specificity
D005415:Flavins; D010446:Peptide Fragments; D003840:Deoxycholic Acid; D003579:Cytochrome Reductases; D009245:NADH Dehydrogenase