Sökning: id:"swepub:oai:DiVA.org:kth-19721" >
Proton-coupled elec...
Proton-coupled electron transfer from tyrosine in a tyrosine-ruthenium-tris-bipyridine complex : Comparison with Tyrosine(z) oxidation in photosystem II
-
Sjodin, M. (författare)
-
- Styring, Stenbjörn (författare)
- Lund University,Lunds universitet,Biokemi och Strukturbiologi,Centrum för Molekylär Proteinvetenskap,Kemiska institutionen,Institutioner vid LTH,Lunds Tekniska Högskola,Biochemistry and Structural Biology,Center for Molecular Protein Science,Department of Chemistry,Departments at LTH,Faculty of Engineering, LTH
-
Akermark, B. (författare)
-
visa fler...
-
Sun, Licheng C. (författare)
-
Hammarstrom, L. (författare)
-
visa färre...
-
(creator_code:org_t)
- 2000-04-06
- 2000
- Engelska.
-
Ingår i: Journal of the American Chemical Society. - : American Chemical Society (ACS). - 0002-7863 .- 1520-5126. ; 122:16, s. 3932-3936
- Relaterad länk:
-
http://dx.doi.org/10...
-
visa fler...
-
https://urn.kb.se/re...
-
https://doi.org/10.1...
-
https://lup.lub.lu.s...
-
visa färre...
Abstract
Ämnesord
Stäng
- The pH- and the temperature dependence of the rate constant for electron transfer from tyrosine to ruthenium in Ru(II)(bpy)(2)(4-Me-4'CONH-L-tyrosine etyl ester-2,2'-bpy) 2PF(6) was investigated using flash photolysis. At a pH below the tyrosine pK(a) approximate to 10 the rate constant increased monotonically with pH. This increase was consistent with a concerted electron transfer/deprotonation mechanism. Also indicative of a concerted reaction was the unusually high reorganization energy, 2 eV, extracted from temperature-dependent measurements. Deprotonation of the tyrosine group, at pH > pK(a), resulted in a 100-fold increase in rate constant due to a decreased reorganization energy, lambda = 0.9 eV. Also, the rate constant became independent of pH, In Mn-depleted photosystem II a similar pH dependence has been found for electron transfer from tyrosine(Z) (Tyr(Z)) to the oxidized primary donor P680(+). On the basis of the kinetic similarities we propose that the mechanisms in the two systems are the same, that is, the electron transfer occurs as a concerted proton-coupled electron-transfer reaction, and at pH < 7 the Tyr(Z) proton is released directly to the bulk water.
Ämnesord
- NATURVETENSKAP -- Biologi (hsv//swe)
- NATURAL SCIENCES -- Biological Sciences (hsv//eng)
Nyckelord
- water oxidation
- involvement
- chemistry
- dynamics
Publikations- och innehållstyp
- ref (ämneskategori)
- art (ämneskategori)
Hitta via bibliotek
Till lärosätets databas