Towards the laser photochemistry of the cornea: studies of the most common and highly absorbing aliphatic amino acids in collagen

Abstract

Abstract The photochemical properties of various aliphatic amino acid residues common in collagen (Gly, Pro, Ala and Hyp), those with high absorption (Arg, Lys and His) and some others, as well as two dipeptides (Gly-Pro and Pro-Gly) have been studied in neutral aqueous solution using 193 nm excimer laser irradiation. The quantum yields for decomposition and electron ejection (0.02–0.20) are determined and the relative probability of photochemical damage of specific residues estimated. The peptide bond is likely to be the main target in collagen. Its scission could be the most important photochemical reaction taking place at 193 nm laser irradiation of the cornea.