Non-enzymic glycation of fibrous collagen: reaction products of XXXX and @entity8690 .

@entity1 @entity23032 @entity6 @entity8690 @entity8759 @entity413
Non-enzymic glycation of collagen involves a series of complex reactions ultimately leading to the formation of intermolecular cross-links resulting in changes in its physical properties. During analysis for the fluorescent cross-link @entity23032 we identified the presence of an additional component (Cmpd K) in both @entity413 and @entity8690 incubations. Cmpd K was formed more quickly than @entity23032 in @entity413 incubations and more slowly than @entity23032 in @entity8690 incubations. Cmpd K represented 45% of the total fluorescence compared with 15% for @entity23032 in @entity413 incubations and 25% of the total fluorescence compared with 30% for @entity23032 in the @entity8690 incubations. Cmpd K is not an artefact of in vitro incubations, as it was shown to be present in dermal tissue from @entity6 @entity1 . Subsequent high-resolution h.p.l.c. analysis of @entity413 -incubated collagen revealed Cmpd K comprise two components ( @entity8759 ). Further, a similar analysis of Cmpd K from the @entity8690 incubations revealed two different components (K3 and K4). These differences indicate alternative mechanisms for the reactions of @entity413 and @entity8690 with collagen. The amounts of these fluorescent components and the @entity23032 cross-link determined for both @entity413 and @entity8690 glycation were found to be far too low (about one @entity23032 molecules per 200 collagen molecules after 6 months incubation with @entity413 ) to account for the extensive cross-linking responsible for the changes in physical properties, suggesting that a further additional series of cross-links are formed. We have analysed the non-fluorescent high-molecular-mass components and identified a new component that increases with time of in vitro incubation and is present in the skin of @entity6 @entity1 . This component is present in sufficient quantities (estimated at one cross-link per two collagen molecules) to account for the changes in physical properties occurring in vitro.
