Nitrogenase activity in extracts of heterocystous and non-heterocystous blue-green algae

✍ Scribed by Haystead, A. ;Robinson, R. ;Stewart, W. D. P.

• Publisher: Springer-Verlag
• Year: 1970
• Weight: 448 KB
• Volume: 74
• Category: Article
• ISSN: 0003-9276
• DOI: 10.1007/bf00408884

✦ Synopsis

Cell-flee extracts capable of acetylene reduction and cyanide reduction have been prepared from heterocystous (Anabaena cylindrica) and non-heteroeystous (Plectonema boryanum 594) blue-green algae. Extracts from Anabaena were obtained from cultures grown in bulk under aerobic conditions, while the Plectonema cultures were grown in bulk on nitrate-nitrogen, then washed free from nitrate and sparged with A/CO 2 for 40 h after which time maximum nitrogenase activity was detected. The nitrogenases of both algae are similar and resemble in many respects nitrogenases from bacteria and legumes. Activity is located primarily in a 40,000 x g • 15 rain supernatant fraction and the rate of C2H 2 reduction observed is about 10 per cent of whole cell activity. ATP and a source of reducing power (Na~S20a) are required for efficient functioning of the enzyme. ATP-dependent hydrogen evolution occurs, the extracts are cold labile and highly sensitive to oxygen and the oxygen inhibition is irreversible.