Isolation and sequence of a novel human chondrocyte protein related to mammalian members of the chitinase protein family

Bo Hu, Kien Trinh, William F. Figueira, Paul A. Price*

*Corresponding author for this work

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Abstract

We describe the isolation of a novel protein from the conditioned medium of human articular cartilage chondrocytes in primary culture. This 39-kDa protein has the N-terminal sequence YKL, which we have termed YKL. 39. The 1434-nucleotide sequence of the YKL-39 cDNA predicts a 385-residue initial translation product and a 364-residue mature YKL-39. The amino acid sequence of YKL-39 is most closely related to YKL-40, followed by macrophage chitotriosidase, oviductal glycoprotein, and macrophage YM-1. All five proteins share significant sequence identity with bacterial chitinases and have the probable structure of an (αβ)8 barrel. YKL-39 lacks the active site glutamate, which is essential for the activity of chitinases, and as expected has no chitinase activity. The highest level of YKL-39 mRNA expression is seen in chondrocytes, followed by synoviocytes, lung, and heart. YKL-39 accounts for 4% of the protein in chondrocyte-conditioned medium, prostromelysin accounts for 17%, and YKL-40 accounts for 33%. In contrast to YKL-40, YKL-39 is not a glycoprotein and does not bind to heparin.

Original languageEnglish (US)
Pages (from-to)19415-19420
Number of pages6
JournalJournal of Biological Chemistry
Volume271
Issue number32
DOIs
StatePublished - Aug 27 1996

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ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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