[Role of ferredoxin in the metabolism of hydrogen by Rhodospirillum rubrum].

Ferredoxin was purified after isolation from the cells of Rhodospirillum rubrum grown under photoheterotrophic conditions; A385/A280 in the absorption spectrum was not less than 0.53; the molecular weight was ca. 7700; E0' (pH 7.0)--430 mv. Ferredoxin was easily reduced in the presence of dithionite and provided a high rate of NADP reduction by pea chloroplasts. The extracts of R. rubrum containing ferredoxin or the extracts, to which it was added, reduced NAD in the presence of hydrogen and evolved H2 in the presence of NAD(P)H. ATP or light were required for the evolution of H2 from NAD(P)H.