Studies of copper transport in cultured bovine chondrocytes

Rose S. Fife, Stephanie Moody, Deborah Houser, Carmen Proctor

Research output: Contribution to journalArticle

9 Scopus citations

Abstract

Copper serves as the cofactor for a number of important enzymes in cartillage, as well as in other tissues, including lysyl oxidase, superoxide dismutase, and cytochrome oxidase. Ceruloplasmin is resposible for the transport of approx. 95% of the copper in serum, but the mechanisms for intracellular copper transport are unknown. We have demonstrated recently that a high-molecular-weight cartilage glycoprotein, referred to as CMGP, has regions of sequence homology with ceruloplasmin. CMGP also binds copper and has at least some oxidase activity similar to that of ceruloplasmin. Other tissues synthesize intracellular ceruloplasmin-like proteins. The present report represents part of an effort examine the hypothesis the CMGP is a copper transport protein in chondrocytes and to characterize the enzymatic activities of CMGP. These studies demonstrate that CMGP is the principal chondrocyte protein labeled by 67Cu in vitro and that the label is localized to the mitochondria, cytosol, and membrane fractions of sucrose gradients, suggesting copper transport through the cell. In parallel experiments, [3H]leucine was incorporated into proteins corresponding to the subunits and fragments of CMGP, as described previously, and in a similar distribution among the subcellular fractions as labeled copper. Additionally, CMGP has oxidase and ferroxidase activities similar to those of ceruloplasmin.

Original languageEnglish (US)
Pages (from-to)19-22
Number of pages4
JournalBBA - General Subjects
Volume1201
Issue number1
DOIs
StatePublished - Sep 28 1994

Keywords

  • Cartilage, Glycoprotein
  • Chondrocyte
  • Copper
  • Metabolism

ASJC Scopus subject areas

  • Biochemistry
  • Biophysics
  • Molecular Biology

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