Abstract
A typical example of non-enzymatic change of collagen is glycation (the Maillard reaction, formation of advanced glycation end products) resulting from the reaction of sugars with the F-amino group of lysine. Posttranslational non-enzymatic modifications of collagen by sugars were studied.
Collagenous tissues were incubated as a test protein separately with both glucose and ribose. The collagen mixture was digested by bacterial collagenase and separated by reversed-phase HPLC (in a Jupiter Proteo 90 A column).
The eluate from this HPLC separation was collected as seven fractions and consecutively analysed by CE in a bare fused silica capillary (57/50 cm. x 75 min id) using 100 mM sodium 1-heptanesulfonate in 100 mM phosphate buffer, pH 2.5 (NaH2PO4 adjusted to pH by phosphoric acid). The chromatographic and electromigration behaviour of individual peptides varied considerably.
This offline HPLC-CE coupling made it possible to discover minor changes in the structure of collagen caused by posttranslational modifications. A new HPLC-CE technique for peptide analysis was developed, and applied to the identification of posttranslational modifications in slowly metabolised test proteins.