Formylmethanofuran dehydrogenase from methanogenic bacteria, a molybdoenzyme

Abstract
Formylmethanofuran dehydrogenase, a key enzyme of methanogenesis, was purified 100‐fold from methanol grown Methanosarcina barkeri to apparent homogeneity and a specific activity of 34 μmol·min−1·mg protein−1. Molybdenum was found to co‐migrate with the enzyme activity. The molybdenum content of purified preparations was 3–4 nmol per mg protein equal to 0.6–0.8 mol molybdenum per mol enzyme of apparent molecular mass 200 kDa. Evidence is presented that also formylmethanofuran dehydrogenase from H2/CO2 grown Methanobacterium thermoautotrophicum (strain Marburg) is a molybdoenzyme.