Photoinduced electron transfer in the Zn-substituted cytochrome c Ru(NH sub 3 ) sub 5 (His-33) derivative studied by phosphorescence and optically detected magnetic resonance spectroscopy

Journal Article · Wed May 23 04:00:00 EDT 1990 · Journal of the American Chemical Society; (USA)

DOI:https://doi.org/10.1021/ja00167a035· OSTI ID:6611888

Zang, Lihsin; Maki, A H ^[1]

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1. Univ. of California, Davis (USA)

The temperature dependence of long-range quenching of the photoexcited triplet state of Zn-substituted cytochrome c by Ru{sup III}(NH{sub 3}){sub 5} covalently attached to histidine-33 has been studied by monitoring the phosphorescence decay kinetics of the electron donor {sup 3}ZnP{sup *}. A temperature-independent triplet quenching process, possibly due to electron transfer facilitated by nuclear tunneling, is observed between ca. 10 and 100 K with a rate constant of 3.6 {plus minus} 0.2 s{sup {minus}1}. Other possibilities for the quenching in this range are energy transfer to an as yet unidentified acceptor state of the Ru{sup III} complex or magnetic dipole induced quenching by the paramagnetic Ru{sup III} complex. Thermally activated quenching, which is attributed to electron transfer, occurs above 100 K. Two regions of Arrhenius-like behavior are observed with a transition at ca. 150 K from E{sub a} = 1.6 kcal/mol to E{sub a} = 5.6 kcal/mol.

• OSTI ID: 6611888
• Journal Information: Journal of the American Chemical Society; (USA), Journal Name: Journal of the American Chemical Society; (USA) Vol. 112:11; ISSN 0002-7863; ISSN JACSA
• Country of Publication: United States
• Language: English

Related Subjects

550200* -- Biochemistry
59 BASIC BIOLOGICAL SCIENCES
CHEMICAL REACTIONS
CYTOCHROMES
DATA
DATA ANALYSIS
ELECTRON TRANSFER
ELEMENTS
EXPERIMENTAL DATA
INFORMATION
MEASURING INSTRUMENTS
MEASURING METHODS
METALS
NUMERICAL DATA
ORGANIC COMPOUNDS
PHOTOCHEMICAL REACTIONS
PIGMENTS
PLATINUM METALS
PROTEINS
QUENCHING
RUTHENIUM
TEMPERATURE DEPENDENCE
TRANSITION ELEMENTS