title: Evidence for increased proteolytic activity in ageing human fibroblasts.
abstract: We have shown that ultrastructural changes accompany ageing in the human fetal lung fibroblast strain MRC-5. In order to further characterise these changes a method has been devised to prepare subcellular fractions from MRC-5 fibroblasts using a discontinous gradient of metrizamide preceded by a low-speed centrifugation. An investigation was carried out to compare subcellular fractions prepared from early-passage and senescent cells. Proteolytic activity associated with lysosomes and soluble proteolytic activity were found to be increased in senescent cells.
mesh_terms: D000135:Acid Phosphatase / Q000378:metabolism; D000375:Aging; D002478:Cells, Cultured; D004247:DNA / Q000378:metabolism; D005333:Fetus / Q000648:ultrastructure; D005347:Fibroblasts / Q000201:enzymology / Q000378:metabolism / Q000648:ultrastructure*; D006651:Histocytochemistry; D006801:Humans; D008168:Lung / Q000648:ultrastructure; D009708:Nucleotidases / Q000378:metabolism; D011506:Proteins / Q000378:metabolism*; D013385:Succinate Dehydrogenase / Q000378:metabolism
chemical_list: D011506:Proteins; D004247:DNA; D013385:Succinate Dehydrogenase; D009708:Nucleotidases; D000135:Acid Phosphatase