Reaction sequences from light absorption to the cleavage of water in photosynthesis

✍ Scribed by H. T. Witt; E. Schlodder; K. Brettel; Ö. Saygin

• Publisher: Springer
• Year: 1986
• Tongue: English
• Weight: 893 KB
• Volume: 10
• Category: Article
• ISSN: 0166-8595
• DOI: 10.1007/bf00118312

✦ Synopsis

The reaction sequence between the primary electron acceptor, the oxidized Chlorophyll-a_T and the terminal electron donor . . 11'

the water splzttlng enzyme system S, is being described in the range from nanoseconds to milliseconds.

For the cleavage of water Chlorophyll-a~i± extracts four electrons in four turnovers from the enzyme system S responsible for the water oxidation.

For each extraction the electron is moved step by step along the chain that connects the Chlorophyll-a__ center with that of S.

Beglnnlng with the transfer from the immedlate + + donor D , to Chl-a , the subsequent transfer from D~ to DI II + z 1 ends in ~he electron transfer from S to D 2. This final act establishes in S the oxidizing equivalent, probably in the form of oxidized manganese.

Coupled with these acts is an intrinsic proton release and a surplus charge formation.

After the generation of the 4th oxidizing equivalent in a concerted final action the evolution of 02 from water takes place.

Correlations between the events are described quantitatively.