PROGRESSIVE CHANGES IN SECONDARY CONFORMATION AND COMPOSITION OF THE SENILE CATARACTOUS HUMAN LENS CAPSULES

The lens capsules of senile cataractous patients were differentiated i nto three progressive grades of immature (I, II and III) and two progr essive grades of mature I' and II') groups using Fourier transform inf rared (FT-IR) microspectroscopy with Fourier self-deconvolution and cu rve-fitting algorithms, according to the changes in IR peak position a nd its structural composition. The secondary conformation of both imma ture-II and mature-I' cataractous human lens capsules was found to cha nge significantly when enhancing the beta-sheet structure but simultan eously decreasing the beta-turn structures, as compared with the compo sition of normal human and immature-I cataractous lens capsules. The i ncrease in beta-sheet structural proportion might possibly be attribut able to the age-related cataractogenesis. We also found that the IR pe ak at 1651 cm(-1) assigned to a-helix shifted to 1647 cm(-1) that corr esponded to disordered structure, but the IR peak at 1662 cm(-1) due t o beta-turn structure disappeared and another new IR peak assigned to alpha-helix structure appeared at 1656 cm(-1), for both immature-III a nd mature-II' cataractous lens capsules. It increased the compositions of beta-sheet and disorder structure and simultaneously decreased the triple helix and beta-turn structures, but maintained the same level in alpha-helix structure. This suggests that FT-IR microspectroscopy c an act as a potential tool to exactly differentiate the maturity of se nile cataractous human lens capsules according to the changes in IR pe ak position and compositions in amide I band.