Skip Navigation

This Article
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Alert me to new issues of the journal
Right arrow Add to My Personal Archive
Right arrow Download to citation manager
Right arrowRequest Permissions
Google Scholar
Right arrow Articles by Shigemori, K.
Right arrow Articles by Kawamori, A.
Right arrow Search for Related Content
PubMed
Right arrow Articles by Shigemori, K.
Right arrow Articles by Kawamori, A.
Agricola
Right arrow Articles by Shigemori, K.
Right arrow Articles by Kawamori, A.
Social Bookmarking
Add to CiteULike   Add to Connotea   Add to Del.icio.us  
What's this?

Plant and Cell Physiology, 1997, Vol. 38, No. 9 1007-1011
© 1997

pH and Temperature Dependence of Tyrosine Z Decay Kinetics in Tris-Treated PSII Particles Studied by Time-Resolved EPR

Kazuhito Shigemori1, Hiroyuki Mino2 and Asako Kawamori1,3

1 Faculty of Science, Kwansei Gakuin University Nishinomiya, 662 Japan
2 Photosynthetic Research Laboratory, The Institute of Physical and Chemical Research (RIKEN) Wako, Saitama, 351-01 Japan

3Correspondence: Faculty of Science, Kwansei Cakuin University, Uegahara 1-1-155, Nishinomiya, 662 Japan.

The decay kinetics of tyrosine Z (Yz) in Tris-treated Photosystem II particles were measured by time-resolved EPR at different pH values (pH 5.5 to 7.5) between 230 and 297 K. Yz induced by laser flashes decayed in a biphasic wav; t1/2 values were about 100 ms in the fast phase and about 1 s in the slow one, respectively, at room temperature. The fast phase was attributed to a recombination of charges on Yz and Q–A. The activation energies for the reaction of Yz with Q–A between 245 and 297 K have been estimated to be more than 38 kJ mol–1 at pH (>6.5) and less than 32 kJ mol–1 at pH (<6.0), respectively. The activation energy gap between high pH (>6.5) and low pH (<6.0) ranges was found to be {Delta}E=4.4 kJ mol–1. Judging from the fact that pH 6.2 appears to be the border between the high and low pH regions, we suggest that the kinetics of Yz is strongly influenced by the dissociation of the nearby histidine residue.

(Received February 21, 1997; Accepted June 24, 1997)
Add to CiteULike CiteULike   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us    What's this?




Disclaimer:
Please note that abstracts for content published before 1996 were created through digital scanning and may therefore not exactly replicate the text of the original print issues. All efforts have been made to ensure accuracy, but the Publisher will not be held responsible for any remaining inaccuracies. If you require any further clarification, please contact our Customer Services Department.