Photochemical transformations in collagen in the presence of melanin

The influence of UV radiation (254 nm) on collagen from rat tail tendon in the absence and presence of melanin was investigated. It was found that the relative viscosity and fluorescence of collagen decreased, whereas the abs orption/scattering of collagen solution increased during irradiation of the sample. Such changes in the physical properties indicate that photodegrada tion, phototransformation and changes in the conformational state of collag en take place during UV irradiation. The changes in the above properties in the presence of melanin suggest that it makes collagen more resistant to t he action of UV radiation. (C) 1999 Elsevier Science S.A. All rights reserv ed.