Figure 2. Preparation of the crude NADH dehydrogenase (NDH, Fp subcomplex) from carbamoylmethylated complex I.
Complex I was alkylated with iodoacetamide according to the procedure described in Experimental Methods. 100 % ethanol was added to a final concentration of 9% (v/v), and the mixture was incubated at 40 °C for 10 min. The sample was then chilled in an ice-salt water bath for 10 min and subjected to centrifugation at 25,000 rpm for 30 min. The supernatant containing crude NDH was collected and concentrated with Centricon 30. Carbamoylmethylated complex I and crude NDH were subjected to SDS-PAGE using 4–12% Bis-Tris polyacrylamide gel. Lane 1, Carbamoylmethylated complex I (30 μg); lane 2, crude NDH preparation (15 μg) from carbamoylmethylated complex I. M represents a molecular weight marker.