title: Composition of the coenzyme F420-dependent formate dehydrogenase from Methanobacterium formicicum.
abstract: The coenzyme F420-dependent formate dehydrogenase from Methanobacterium formicicum was purified to electrophoretic homogeneity by anoxic procedures which included the addition of azide, flavin adenine dinucleotide (FAD), glycerol, and 2-mercaptoethanol to all buffer solutions to stabilize activity. The enzyme contains, in approximate molar ratios, 1 FAD molecule and 1 molybdenum, 2 zinc, 21 to 24 iron, and 25 to 29 inorganic sulfur atoms. Denaturation of the enzyme released a molybdopterin cofactor. The enzyme has a molecular weight of 177,000 and consists of one each of two different subunits, giving the composition alpha 1 beta 1. The molecular weight of the alpha-subunit is 85,000, and that of the beta-subunit is 53,000. The UV-visible spectrum is typical of nonheme iron-sulfur flavoprotein. Reduction of the enzyme facilitated dissociation of FAD, and the FAD-depleted enzyme was unable to reduce coenzyme F420. Preincubation of the FAD-depleted enzyme with FAD restored coenzyme F420-dependent activity.
mesh_terms: D000445:Aldehyde Oxidoreductases / Q000302:isolation & purification*; D019605:Euryarchaeota / Q000201:enzymology*; D005182:Flavin-Adenine Dinucleotide / Q000378:metabolism; D005560:Formate Dehydrogenases / Q000302:isolation & purification*; D007501:Iron / Q000032:analysis; D046911:Macromolecular Substances; D008667:Metalloproteins / Q000302:isolation & purification*; D008970:Molecular Weight; D008982:Molybdenum / Q000032:analysis; D012256:Riboflavin / Q000031:analogs & derivatives / Q000378:metabolism; D013057:Spectrum Analysis; D013455:Sulfur / Q000032:analysis; D015032:Zinc / Q000032:analysis
chemical_list: D046911:Macromolecular Substances; D008667:Metalloproteins; D005182:Flavin-Adenine Dinucleotide; C015084:coenzyme F420; D013455:Sulfur; D008982:Molybdenum; D007501:Iron; D005560:Formate Dehydrogenases; D000445:Aldehyde Oxidoreductases; D015032:Zinc; D012256:Riboflavin