Ceruloplasmin binds and inactivates matrix metalloproteinase‐2

An interaction between the iron‐binding protein lactoferrin and matrix metalloproteinase‐2 (MMP‐2) suggests that MMP‐2 may interact with other metal binding proteins. To examine this possibility, the copper binding protein ceruloplasmin was examined to determine its effect on MMP‐2 and pro‐MMP‐2. Apoceruloplasmin, and to a lesser extent, holoceruloplasmin, physically interacted with pro‐MMP‐2 in an immunoprecipitation assay. Furthermore, apoceruloplasmin inhibited the protease activity of active MMP‐2, suggesting that ceruloplasmin may regulate the activity of MMP‐2 in vivo .