| First Author | Gray LW | Year | 2009 |
| Journal | Biochem J | Volume | 419 |
| Issue | 1 | Pages | 237-45 |
| PubMed ID | 19076073 | Mgi Jnum | J:149076 |
| Mgi Id | MGI:3847584 | Doi | 10.1042/BJ20081983 |
| Citation | Gray LW, et al. (2009) Copper proteins and ferroxidases in human plasma and that of wild-type and ceruloplasmin knockout mice. Biochem J 419(1):237-45 |
| abstractText | In the blood plasma of humans and rats, ceruloplasmin is the major copper-binding protein and ferroxidase, accounting for 70% of the copper present in the plasma, with the rest binding primarily to albumin and a macroglobulin. Systematic studies with fresh plasma were carried out to compare what occurs in the mouse. C57BL6 mice had half as much copper and pPD (p-phenylene diamine) oxidase activity as humans and rats, 20-40% as much ferroxidase activity as humans (determined using three different assays) and less inhibition by azide. Plasma from ceruloplasmin knockout mice had no pPD oxidase activity, but retained >50% ferroxidase activity (which was not as affected by azide). Modelling of mouse ceruloplasmin against the known X-ray structure of human ceruloplasmin indicated subtle but potentially significant changes in the pPD- and azide-binding sites. Purification and in-gel assays after native PAGE confirmed that mouse ceruloplasmin had ferroxidase activity but revealed an additional ferroxidase in ceruloplasmin knockout mouse plasma, which is also seen in size-exclusion chromatography. In the wild-type mouse, the 'ceruloplasmin' peak contained approximately 55% of the total copper, but ceruloplasmin knockout plasma exposed a major additional peak (180 kDa) which co-eluted with ferroxidase activity. Two other ferroxidases (700 and 2000 Da) were also detected in mouse and human plasma. Mammalian blood thus contains copper components and ferroxidases not reported previously. |
