Caeruloplasmin

Caeruloplasmin
Strip/surface model with copper (blue) according to PDB 1KCW
Existing structural data 1KCW, 2J5W
Properties of the human protein
Mass/Length Primary structure	132 kilodaltons / 1046 amino acids
Cofactor	8 Cu2+
Identifier
Gene names	CP; CP-2
External IDs	OMIM:117700 UniProt:P00450 MGI:88476
Enzyme classification
EC, Category	1.16.3.1, oxidoreductase
Response type	Oxidation
Substrate	4 Fe2+ + 4 H+ + O2
Products	4 Fe3+ + 2 H2O
Occurrence
Homology family	Ceruloplasmin
Superordinate taxon	Neumünder
Orthologist
	Human	House Mouse
Entrez	1356	12870
Ensembl	ENSG000047457	ENSMUSG000003617
UniProt	P00450	Q61147
Refseq (mRNA)	NM_000096	NM_001042611
Refseq (Protein)	NP_000087	NP_001263177
Genlocus	Chr 3: 149.16 – 149.22 Mb	Chr 3: 19.96 – 20.01 Mb
PubMed search	1356	12870

Caeruloplasmin (CP)(Latin caeruleus ‘blue’), in other spellings ceruloplasmin, coeruloplasmin, or caeruloplasmin, is a plasma protein of all newborns. This bluish enzyme is an oxidase, and is also called ferroxidase or iron(II):oxygen oxidoreductase.^[1] It acts as a copper store, helping to transport iron out of cells where it had accumulated. It is formed in the liver and brain and already receives six or seven copper ions post-translationally during its biosynthesis and can transport up to 8 copper ions per molecule. In the case of copper deficiency in the body, on the other hand, only unstable apocoeruloplasmin is formed.

Caeruloplasmin possesses a copper-dependent oxidase activity (ferroxidase)^[2]which enables the oxidation of Fe2+ to Fe3+ and thus contributes to its transport into the blood plasma in association with transferrin, which can only transport Fe3+ ions.

Serum caeruloplasmin is determined in the diagnosis of iron and copper metabolism. Serum levels may increase in severe infectious diseases and inflammations (as part of the acute phase reaction) as well as during pregnancy.

In contrast, in Wilson’s disease (hepatolenticular degeneration), decreased values below 0.2 g/l are found.

Diseases

Hereditary deficiency of coeruloplasmin due to a genetic mutation, or decreased production due to liver disease, leads to increased pathological accumulation of iron in the body, including in reticuloendothelial cells and hepatocytes.^[3]

In the case of a complete loss of ferroxidase activity, which is also associated with increased iron storage in the body, one speaks of acaeruloplasminemia.

Individual references

1. ↑ David N. Caplan, Otto Rapalino, Amel Karaa, Rachel P. Rosovsky et al: Case 35-2020: A 59-Year-Old Woman with Type 1 Diabetes Mellitus and Obtundation, New England Journal of Medicine 2020, Volume 383, Issue 20, November 12, 2020, Pages 1974-1983, DOI: 10.1056/NEJMcpc2002412
2. ↑ Nathan E. Hellman and Jonathan D. Gitlin: Ceruloplasmin metabolism and function. Annual Review of Nutrition
   Vol. 22: 439-458 doi:10.1146/annurev.nutr.22.012502.114457
3. ↑ Caeruloplasmin.In: Online Mendelian Inheritance in Man. (English).