PROCOLLAGEN AND COLLAGEN PRODUCED BY NORMAL BOVINE CORNEAL STROMA FIBROBLASTS IN CELL-CULTURE

  • 1 January 1980
    • journal article
    • research article
    • Vol. 19  (2) , 192-202
Abstract
Procollagen and collagen were isolated from the culture medium of normal bovine corneal stromal fibroblasts. DEAE-cellulose chromatography was used to separate the collagen molecules from the different procollagens. One collagen and 4 procollagen peaks were isolated and biochemically characterized. All the procollagen fractions and the collagen fraction yielded, after limited pepsin or chymotrypsin digestion followed by CNBr [cyanogen bromide] digestion, molecules corresponding to (.alpha.1)2.alpha.2. Only type I collagen is found in the growth medium of bovine corneal stromal fibroblast cultures. Each of the individual procollagen peaks contained pro-.alpha. chains having MW of 120,000, 150,000, 165,000, 180,000 and 190,000, according to their elution position on DEAE-cellulose. The presence of type I procollagen molecules having pro-.alpha. chains of 165,000, 180,000 and 190,000 daltons was not previously reported and probably represents higher MW precursor intermediates. The amino acid compositions of the different procollagen fractions are unique, and each contains relatively large amounts of cysteine and tryptophan. Carbohydrate analysis, CNBr peptide analysis, EM of SLS[segment long spacing]-crystallites and SDS[sodium dodecyl sulfate]-polyacrylamide gel electrophoresis were used to further characterize the procollagen and collagen molecules.