Identification of the collagenous proteins synthesized by cultured cells from human skin.

Cells cultured from human skin synthesize precursor forms of types I and III collagens. After denaturation and reduction, the polypeptide chains obtained from these molecules had molecular weights estimated to be 140,000 and 120, 000. The larger chains, the pro alpha chains, are believed to be derived from the original precursor molecules. The smaller chains arise from altered forms, p-collagens, that may be normal intermediates in the conversion of both procollagens to collagens I and III.