CAPILLARY ELECTROPHORESIS OF LARGE CYANOGEN-BROMIDE PEPTIDES OF FIBER-FORMING COLLAGENS WITH SPECIAL REFERENCE TO CROSS-LINKING

Cyanogen bromide (CNBr) peptides derived from collagen types I and III and having a relative molecular mass of more than 13 500 exhibit a li near relationship between molecular mass and migration time. This beha vior is similar to the elution of CNBr peptides of collagen types I an d III from wide pore (30 nm) C-18 reversed-phase columns. The electrop horetic procedure is very rugged and the linearity is preserved over t he pH range 2.0-2.5, with a background electrolyte concentration of 20 -100 mmol/l and an applied voltage of 8-25 kV [per 70 cm (effective le ngth 63 cm)x 75 mu m I.D. capillary]. Modification of the inner capill ary surface or addition of an organic modifier ruins the separation, T he separation mechanism is apparently multimodal, as no correlation be tween the number of total amino acid residues forming a peptide, the n umber of proline and hydroxyproline residues or the number of glycines could be established. Also, there is no secondary structure involved, as the results with native and denatured peptides were the same. Appl ication of this approach to reveal higher molecular mass peptides (sim ilar to 40 000) in rat tail tendons of two-year-old rats compared with three-month-old rats is presented.