Imoto T, Forster L S, Rupley J A, Tanaka F
Proc Natl Acad Sci U S A. 1972 May;69(5):1151-5. doi: 10.1073/pnas.69.5.1151.
The bulk of the fluorescence of lysozyme is located in Trp 62 and Trp 108. By examination of the fluorescence of derivatives in which Trp 62 and/or Trp 108 are specifically oxidized, it has been possible to detect a pH-dependent interaction between tryptophan residues. This interaction is interpreted as energy transfer from Trp 108 to Trp 62.