Evidence for a membrane bound NADH-plastoquinone-oxidoreductase inChlamydomonas reinhardiiCW-15

✍ Scribed by Doris Godde

• Book ID: 104760353
• Publisher: Springer
• Year: 1982
• Tongue: English
• Weight: 642 KB
• Volume: 131
• Category: Article
• ISSN: 0302-8933
• DOI: 10.1007/bf00405878

✦ Synopsis

NADH-plastoquinone-oxidoreductase bound to the membrane fraction of Chlamydomonas reinhardii CW-I 5 has been solubilized with triton X-100. By treatment with high concentrations of MgCI2 and KC1 and (NH4)2SO 4 fractionation the enzyme could be enriched 8-10-fold. Spectral properties indicated a flavoprotein probably containing Fe-S groups. The enzyme oxidizes NADH and NADPH with various quinones as electron acceptors. Plastoquinone 1 is an effective electron acceptor, whereas ubiquinone i is only reduced with low activity. The enzyme is sensitive to rotenone and thenoyltrifluoroacetone, both inhibitors of ubiquinone reduction by mitochondrial dehydrogenases. As the bound enzyme is sensitive to inhibitors of photosynthetic electron flow, the enzyme is assumed to be responsible for light driven hydrogen evolution at the expense of NADH generating substrates.