The effect of glycosaminoglycans (GAG) on the intramolecular bindings of collagen.

The subfractions of collagen (alpha, beta and gamma components) precipitated from neutral collagen solution by gelation corresponded to those of collagen precipitated in the same conditions (ion environments) and in the presence of chondroitin-4-sulphate. Collagen fibrils precipitated delayed in the presence of heparin poor in beta chains and rich in alpha chains. The delaying effect of oversulphated GAG on the in vitro fibril formation can be explained by the release or prevention of ion-type intramolecular bonds of collagen. The possible in vivo significance of the above bonds is discussed.

The effect of glycosaminoglycans on the in vitro fibril formation of collagen type I and type III.

The effect of glycosaminoglycans (GAG) on the in vitro collagen fibril formation of type I and type III collagen extracted from rat skin was studied by measuring the optical absorbancy change of collagen-GAG solution during the fibrillary precipitation and following the electronmicroscopic structure of collagen fibrils. The main difference between type I and type III collagen was found in the kinetic of fibrillary precipitation mainly during the logarithmic growth ("log") period of fibril formation. Chondroitin sulphate-A (CSA) shortened this phase and affected especially type III collagen which has a longer "log" period. No difference was found in the electronmicroscopic structure of collagen fibrils. The supposed biological significance of the results is briefly discussed.