What does ceruloplasmin mean?
Ceruloplasmin is a copper-containing protein, technically a glycoprotein enzyme, produced chiefly by the liver and released into the bloodstream. Its name reflects its distinctive sky-blue colour, which comes from the six to seven copper atoms each molecule carries; indeed, it accounts for the vast majority — often cited as around 95% — of all copper circulating in human plasma. Beyond simply transporting copper, ceruloplasmin plays an active biochemical role as a ferroxidase: it oxidizes ferrous iron (Fe2+) into ferric iron (Fe3+), the form that must be bound by transferrin before iron can be safely transported and stored in the body. Clinically, measuring serum ceruloplasmin levels is a standard diagnostic test, most famously in suspected cases of Wilson's disease, a genetic disorder in which copper accumulates to toxic levels because ceruloplasmin production is impaired. The word belongs firmly to medical and biochemical vocabulary and is rarely encountered outside those settings.
nounA blue copper-containing glycoprotein found in blood plasma that carries the majority of copper in the body and functions as the enzyme ferroxidase, oxidizing iron so it can bind to transferrin.
- A blue copper-containing glycoprotein synthesized mainly by the liver, present in blood plasma, which transports most of the body's circulating copper and acts as ferroxidase in iron metabolism.
"The patient's serum ceruloplasmin level was markedly low, supporting a diagnosis of Wilson's disease."
"Because ceruloplasmin binds roughly 95% of the copper in human plasma, low levels can point to Wilson's disease."
"As a ferroxidase, ceruloplasmin converts ferrous iron into the ferric form required for loading onto transferrin."
Rarely used; typically only in contexts comparing different forms of the protein across samples or species.
"Comparative studies have characterized ceruloplasmins from several mammalian species."
It's one of the very few proteins that is actually blue — its name comes from the Latin for 'sky-blue', thanks to the copper it carries.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of ceruloplasmin
The term ceruloplasmin was coined in the mid-twentieth century, shortly after the protein was identified in blood plasma, combining the Latin adjective caeruleus ('blue, sky-blue') with 'plasmin' in reference to its presence in blood plasma. The same Latin root caeruleus gives English 'cerulean'. The 'plasma' element derives from the Greek word for something moulded or formed, adopted into scientific terminology for the fluid portion of blood.
How ceruloplasmin is actually used
Strictly a technical term used in biochemistry and medicine, particularly in the workup of Wilson's disease and disorders of iron metabolism. It appears almost exclusively in clinical, laboratory, and scientific contexts rather than general prose.
Easily confused with ceruloplasmin
Ceruloplasmin is a copper-carrying protein in blood plasma, whereas cerulein is a decapeptide related to cholecystokinin used experimentally to induce pancreatitis.