Tyrosine YZ and YD of photosystem II . Comparison of optical spectra to those of tyrosine oxidised by pulsed radiolysis
We have compared the optical spectrum of tyrosine oxidised in aqueous solution by pulsed radiolysis with spectra of redox active tyrosines YZ and YD of photosystem II. This indicates a "tyrosinate" state for these tyrosines and also casts doubt on the assumption that YZ and YD optical spectra are very similar in different photosystem II preparations. It suggests that further optical spectra of YZ in more intact oxygen-evolving preparations are needed before the role of Yz in water oxidation can be clarified. Copyright 1998 Elsevier Science B.V.
Candeias
LP
Gray Laboratory Cancer Research Trust, PO Box 100 Mount Vernon Hospital, Northwood, Middlesex HA6 2JR, UK
Turconi
S
Nugent
JHA