Abstract
Photoexcitation of flavin analogs generates the lowest triplet state (via intersystem crossing from the first excited singlet state) in the nanosecond time domain and with high quantum efficiency. The triplet, being a strong oxidant, can abstract a hydrogen atom (or an electron) from a reduced donor in a diffusion-controlled reaction. If the donor is a redox protein, the oxidation process can be used to initiate an electron transfer sequence involving either intramolecular or intermolecular reactions. If the donor is an organic compound such as EDTA, the neutral flavin semiquinone will be produced by H atom abstraction; this is a strong reductant and can subsequently transfer a hydrogen atom (or an electron) to an oxidized redox protein, thereby again initiating a sequence of intramolecular or intermolecular processes. If flavin photoexcitation is accomplished using a pulsed laser light source, the initiation of these protein electron transfer reactions can be made to occur in the nanosecond to microsecond time domain, and the sequence of events can be followed by time-resolved spectrophotometry to obtain rate constants and thus mechanistic information. The present paper describes this technology, and selected examples of its use in the investigation of redox protein mechanisms are given.
Similar content being viewed by others
References
Ahmad, I., Cusanovich, M. A., and Tollin, G. (1981).Proc. Natl. Acad. Sci. USA 78, 6724–6728.
Cusanovich, M. A., Meyer, T. E., and Tollin, G. (1988). InAdvances in Inorganic Biochemistry, Vol. 7, Heme Proteins (Eichorn, G. L., and Marzilli, L. G., eds), Elsevier, New York, pp. 37–91.
Edmondson, D. E., Barman, B., and Tollin, G. (1972).Biochemistry 11, 1133–1138.
Hazzard, J. T., Marchesini, A., Curir, P., and Tollin, G. (1994a).Biochim. Biophys. Acta 1208, 166–170.
Hazzard, J. T., McDonough, C.A., and Tollin, G. (1994b).Biochemistry 33, 13445–13454.
Hurley, J. K., Salamon, Z., Meyer, T. E., Fitch, J. C., Cusanovich, M. A., Markley, J. L., Cheng, H., Xia, B., Chae, Y. K., Medina, M., Gomez-Moreno, C., and Tollin, G. (1993).Biochemistry 32, 9346–9354.
Jung, J., and Tollin, G. (1981).Biochemistry 20, 5124–5131.
Meyer, T. E., Marchesini, A., Cusanovich, M. A., and Tollin, G. (1991).Biochemistry 30, 4619–4623.
Simondsen, R. P., and Tollin, G. (1983).Biochemistry 22, 3008–3016.
Simondsen, R. P., Weber, P. C., Salemme, F. R., and Tollin, G. (1982).Biochemistry 21, 6366–6375.
Tollin, G., and Hazzard, J. T. (1991).Arch. Biochem. Biophys. 287, 1–7.
Tollin, G., Meyer, T. E., and Cusanovich, M. A. (1986).Biochim. Biophys. Acta 853, 29–41.
Tollin, G., Hurley, J. K., Hazzard, J. T., and Meyer, T. E. (1993).Biophys. Chem. 48, 259–279.
Traber, R., Kramer, H. E. A., and Hemmerich, P. (1982).Biochemistry 21, 1687–1693.
Walker, M. C., Pueyo, J. J., Navarro, J. A., Gomez-Moreno, C., and Tollin, G. (1991).Arch. Biochem. Biophys. 287, 351–358.
Walker, M. C., and Tollin, G. (1991).Biochemistry 30, 5546–5555.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Tollin, G. Use of flavin photochemistry to probe intraprotein and interprotein electron transfer mechanisms. J Bioenerg Biomembr 27, 303–309 (1995). https://doi.org/10.1007/BF02110100
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF02110100