Changes induced by ultraviolet light in fluorescence of collagen in the presence of β-carotene

The influence of UV radiation (253.7 nm) on collagen fluorescence in the absence, and presence, of β-carotene was investigated. It was found that UV radiation of 253.7 nm causes irreversible destruction of tyrosyl and phenylalanyl residues. The fluorescence of collagen (excitation at 275 nm, emission at 305 nm) decreased rapidly during irradiation and a new fluorescence large band at 400–500 nm formed under UV radiation. Smaller changes in the fluorescence of collagen in the presence of β-carotene suggest that it makes collagen less sensitive to the action of UV radiation.