title: Component A2 of the methylcoenzyme M methylreductase system from Methanobacterium thermoautotrophicum.
abstract: Component A2 of the methylcoenzyme M methylreductase system of Methanobacterium thermoautotrophicum has been purified 370-fold by liquid chromatography. Homogeneity was obtained by anaerobic preparative polyacrylamide gel electrophoresis. Component A2 is a colorless, air-stable protein consisting of a single polypeptide as indicated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The relative molecular mass of the native protein was determined by high-performance, size exclusion chromatography to be Mr 52,000; on sodium dodecyl sulfate-polyacrylamide gel electrophoresis a value of Mr 59,000 was obtained. When cell extract was subjected to N6-ATP-agarose affinity chromatography the methylcoenzyme M methylreductase system was resolved into two fractions; one of them was component A2. This work provides a new operational definition for component A2, i.e., its characteristic chromatographic behavior on N6-ATP-agarose. However, its functional definition is its ability to reconstitute the methylreductase activity with components A1, A3, and C. Several attempts to assign a role to component A2 are reported.
mesh_terms: D002846:Chromatography, Affinity; D004591:Electrophoresis, Polyacrylamide Gel; D019605:Euryarchaeota / Q000201:enzymology*; D008970:Molecular Weight; D010088:Oxidoreductases / Q000032:analysis*
chemical_list: D010088:Oxidoreductases; C023895:methyl coenzyme M methylreductase