Procollagen and collagen produced by a teratocarcinoma-derived cell line,TSD4: Evidence for a new molecular form of collagen

Procollagen and collagen were isolated from the culture medium and cell layer of line TSD4 (obtained from mouse teratocarcinoma OTT6050). SDS-polyacrylamide gel electrophoresis of the highly purified procollagen fraction demonstrated that the fraction is composed of θ chains (150,000 daltons), pro α chains (130,000 daltons), and α chains (100,000 daltons). Limited pepsin digestion of this fraction yielded a single species of collagen molecules having a chain composition (α1)₃, as did collagen isolated from the cell layer. Each α1 chain appears to be slightly larger than α1 chains from calf or human type I and type III collagen. Amino acid analysis and cyanogen bromide peptide profiles of pepsin-treated TSD4 collagen demonstrated significant differences from those of other collagens (II, III, IV) of the type α1(X)₃, although similar to that of the α1 chain of type I collagen, α1(I)]₂α2. Taken together, acrylamide gel electrophoresis, amino acid composition, electron microscopy, and cyanogen bromide peptide analysis indicate that this material represents a new molecular species of collagen not previously characterized, probably related to α1(I)]₃.