BIOCHEMICAL-ALTERATIONS IN COLLAGEN-IV INDUCED BY IN-VITRO GLYCATION

Non-enzymic interactions of carbohydrates and proteins are a major fea ture of cumulative modification in basement membranes in the course of diabetic microvascular complications. To evaluate the significance of both glycation and glycoxidation reactions for subsequent alterations of biochemical properties, we examined the effects of in vitro glycat ion on distinct collagen IV domains under different experimental condi tions. The 7 S domain and the major triple-helical domain from human p lacental collagen IV were incubated for various time intervals up to 1 4 days at 37 degrees C in the presence of different concentrations of either glucose or ribose under oxidative and antioxidative conditions. Carbohydrate-induced non-enzymic modification in two collagen IV doma ins was revealed by increased cross-linking and fluorescence. In addit ion, these non-enzymic modifications apparently have a major impact on molecular conformation and thermal stability of collagen IV, which in turn might influence both cell-matrix interactions and matrix assembl y.