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ENHANCEMENT OF THE NON‐TRYPTOPHAN FLUORESCENCE OF HUMAN LENS PROTEINS AFTER NEAR‐UV LIGHT EXPOSURE *
Author(s) -
Zigman Seymour,
Groff Jeannine,
Yulo Teresa
Publication year - 1977
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.1977.tb07522.x
Subject(s) - tryptophan , fluorescence , chemistry , lens (geology) , polyacrylamide gel electrophoresis , crystallin , gel electrophoresis , biochemistry , photochemistry , biophysics , amino acid , biology , enzyme , optics , paleontology , physics
. In this work, the non‐tryptophan fluorescence (360 nm excited; 440 nm emitted) of human lens proteins was found to be intensified by exposing whole lens homogenates to near‐UV light in the presence of tryptophan photoproducts. The induced fluorescence accumulates mainly in the soluble phase proteins, whereas in aging and brown cataractous lenses, the major fluorescence is found in the insoluble proteins. Using SDS‐polyacrylamide gel electrophoresis with densitometric and fluorescence scanning techniques, the polypeptide chains of the three major protein fractions were analyzed for their specific non‐tryptophan fluorescences. The same chains were found in all fractions. Two chains (11,000 and 45,000 daltons) were found to accumulate most of the induced fluorescence. These also contained the greatest intrinsic fluorescence initially. The data indicates that specific polypeptide chains in the lens proteins are most sensitive to modifications due to their exposure to near‐UV light in the presence of tryptophan photoproducts.