The effect of carotenoid pigments on photooxidations of some photosynthetic bacteria

✍ Scribed by L.A. Feldman; E.S. Lindstrom

• Publisher: Elsevier Science
• Year: 1964
• Weight: 394 KB
• Volume: 79
• Category: Article
• ISSN: 0926-6577
• DOI: 10.1016/0926-6577(64)90007-5

✦ Synopsis

The photooxidase activity of normal and carotenoidless mutants of Rhodopseudomonas spheroides and RhodospirilIum rubrum were compared. With Rhodopseudomonas, carotenoids were shown to act as accessory pigments in indophenol photooxidation. The lack of carotenoids resulted in a greater specific activity of the photooxidase system. In Rhodopseudomonas, carotenoids apparently function as an accessory pigment and as a buffer for the photooxidant. With Rhodospirillum, no accessory pigment flmction could be demonstrated in indophenol photooxidation, and the absence of carotenoids did not result in an increased photooxidase activity. Addition of ammonium sulfate increased the rate of photooxidations in Rhodospirillum but not in Rhodopseudomonas. This apparent difference in carotenoid function probably reflects a difference in carotenoid concentration and/or in membrane structure.