Effect of iron supply on the activities of the nitrate-reducing system from Chlorella

✍ Scribed by C�rdenas, J. ;Rivas, J. ;Paneque, A. ;Losada, M.

• Publisher: Springer-Verlag
• Year: 1972
• Weight: 214 KB
• Volume: 81
• Category: Article
• ISSN: 0003-9276
• DOI: 10.1007/bf00412244

✦ Synopsis

In Chlorella, as in most photosynthetic organisms, the reduction of nitrate to ammonia proceeds sequentially in two independent and well characterized steps, catalyzed by the enzymes of the nitrate-reducing system: 1. the reduction of nitrate to nitrite by the fiavomolybdoprotein NADH-nitrate reductase, and 2. the reduction of nitrite to ammonia by the ironprotein ferredoxin-nitrite reductase. In this communication, it is shown that, in Chlorella, the cellular level of nitrite reductase activity specifically increases in response to the iron content of the culture medium. By contrast, the activity of nitrate reductase is apparently not affected by the concentration of iron in the nutrient solution under the same conditions.