Picture of wind turbine against blue sky

Open Access research with a real impact...

The Strathprints institutional repository is a digital archive of University of Strathclyde research outputs.

The Energy Systems Research Unit (ESRU) within Strathclyde's Department of Mechanical and Aerospace Engineering is producing Open Access research that can help society deploy and optimise renewable energy systems, such as wind turbine technology.

Explore wind turbine research in Strathprints

Explore all of Strathclyde's Open Access research content

Effect of ph on aqueous phenylalanine studied using a 265-nm pulsed light-emitting diode

Macmillan, A.M. and McGuinness, C.D and Sagoo, K. and McLoskey, D. and Pickup, J.C. and Birch, D.J.S. (2008) Effect of ph on aqueous phenylalanine studied using a 265-nm pulsed light-emitting diode. Annals of the New York Academy of Sciences, 1130. pp. 300-304. ISSN 0077-8923

Full text not available in this repository. (Request a copy from the Strathclyde author)

Abstract

Recently, we described the characteristics and application of a 265-nm AlGaN light-emitting diode (LED) operated at 1-MHz repetition rate, 1.2-ns pulse duration, 1.32-μW average power, 2.3-mW peak power, and approximately 12-nm bandwidth. The LED enables the fluorescence decay of weakly emitting phenylalanine to be measured routinely in the condensed phase, even in dilute solution. For a pH range of 1-11, we find evidence for a biexponential rather than a monoexponential decay, whereas at pH 13, only a monoexponential decay is present. These results provide direct evidence for the dominance of two phenylalanine rotamers in solution with a photophysics closer to the other two fluorescent amino acids, tyrosine and tryptophan, than has previously been reported. Although phenylalanine fluorescence is difficult to detect in most proteins because of its low quantum yield and resonance energy transfer from phenylalanine to tyrosine and tryptophan, the convenience of the 265-nm LED may well take protein photophysics in new directions, for example, by making use of this resonance energy transfer or by observing phenylalanine fluorescence directly in specific proteins where resonance energy transfer is inefficient.