The roles of weak light, oxygen and dithiothreitol in the photoreactivation of the oxygen evolving center of tris-washed and 2, 6-dichlorophenol indophenol-treated chloroplasts
✍ Scribed by Takashi Yamashita; Takahiro Kobayashi; Yasuhisa Morita; Toshibumi Shoji
- Publisher
- Springer
- Year
- 1990
- Tongue
- English
- Weight
- 560 KB
- Volume
- 26
- Category
- Article
- ISSN
- 0166-8595
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✦ Synopsis
The inactivated O2-evolving center of Tris-washed chloroplasts was reactivated by DCPIP-treatment and photoreactivation in the presence of Mn 2÷, Ca 2+, DTF and weak light. Many electron donors (Asc and reduced DCPIP, etc.) were found to be suitable substitutes for DTF. By studying the anaerobic inhibition of the reactivation, the electron acceptors 02, NADP ÷, etc. were also found to be essential factors in photoreactivation. Weak light stimulated the chloroplast electron transport from the above-mentioned electron donors to the electron acceptor and effected the photoreactivation. More than 280 electrons were transported to NADP ÷ in the anaerobic photoreactivation of one unit of an O2-ev°lving2÷ . center with 400 Chl. Electron transport in the reactivation was inhibited" .... by omlttmg DTT or Mn 1on, and by adding DCMU. The photoreactivated chloroplasts incorporated about 2 Mn by 400 Chl. Omission of DTT in the reactivation caused chloroplasts in the weak light to bind large amounts of excess Mn.