Heterogeneity of collagen isolated from methylcholanthrene-induced sarcoma.

Rat fibrosarcoma induced by subcutaneous injection of methylcholanthrene was found to contain at least three different types of collagen. Two of them were identified as type I and type III collagens, the third (fraction B) seems to be specific for this tumour. The ratio of type I to type III collagen is lower in fibrosarcoma than in normal rat skin. The number of hydroxyproline residues in alpha 1 (I), alpha 2 (I) and alpha 1 (III) chains of tumour collagen appears to be higher than in the corresponding chains of rat skin collagen. Fraction B is composed of three identical alpha chains connected with disulphide bonds. It contains a relatively low amount of glycine: 234 molecules per 1000 residues. The amount of hydroxyproline and cysteine is similar to that found in the type III collagen.