Peptide-maps of procollagen (I) from corneas and tendons of 17-day-old chick embryos.
Corneas and tendons dissected from 17-day-old chick embryos were labeled with [35S]methionine in the presence of 0.3 mM alpha,alpha'-dipyridyl. The unhydroxylated, 35S-labeled pro alpha chains and alpha chains were isolated by polyacrylamide gel electrophoresis in sodium dodecyl sulfate. The pro alpha and alpha chains were then subjected to peptide-map analysis by proteolytic digestion with trypsin and alpha-chymotrypsin, papain or proteinase K. The peptide-maps derived from cornea and tendon pro alpha 1(I) chains are identical. Similar results were obtained from cornea and tendon alpha 1(I) chains. There were differences in the peptide maps derived from cornea and tendon pro alpha 2(I) chains. However, no difference was observed in alpha 2(I) chains. These results suggest that cornea and tendon pro alpha 1(I) chains are probably identical in primary structures, whereas the cornea pro alpha 2(I) chain may be different from the tendon pro alpha 2(I) chain within pepsin sensitive regions of the procollagen molecule. The reason for difference in the peptide-maps of pro alpha 2(I) chains remain unknown. One of the possible explanations is the variation of posttranslational modification within the propeptides of the pro alpha 2(I) chain. However, this hypothesis needs to be further investigated. Nevertheless, the finding that the peptide-maps of alpha 2(I) chains from tendons and corneas are identical fail to support the two genes hypothesis for pro alpha 2(I) chains.
D000818:Animals; D002642:Chick Embryo; D003315:Cornea / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D010446:Peptide Fragments / Q000302:isolation & purification; D010455:Peptides / Q000378:metabolism*; D011347:Procollagen / Q000378:metabolism*; D013710:Tendons / Q000378:metabolism*; D014018:Tissue Distribution
D010446:Peptide Fragments; D010455:Peptides; D011347:Procollagen