Degradative enzyme activity in isolated chondrocyte populations.
Chondrocytes from adult and immature articular cartilage were separated on the basis of size by rate-zonal centrifugation in a Ficoll density gradient. Lysozomal enzyme activity (acid phosphatase and beta-glucuronidase) was determined in gradient fractions containing chondrocytes of different sizes. Acid phosphatase and beta-glucuronidase activity in mature articular cartilage was greatly increased in small sized cells, located in the superficial tangential zone. In cells from immature calf articular cartilage, there were two peaks of increased activity, on in the superficial tangential zone, the other in the deep radial zone, close to the cartilage bone junction. It is speculated that the small surface cells, with thier high degradative enzyme levels, may explain why the osteoarthritis process starts at the surface.
D000135:Acid Phosphatase / Q000032:analysis*; D000818:Animals; D002356:Cartilage / Q000166:cytology / Q000201:enzymology*; D002417:Cattle; D005966:Glucuronidase / Q000032:analysis*; D008247:Lysosomes / Q000201:enzymology
D000135:Acid Phosphatase; D005966:Glucuronidase