C-reactive protein molecule. Computer model showing the structure of a molecule of human C-reactive protein (CRP). This protein is made up of five sub-units (monomers) arranged in a ring. CRP is a blood plasma protein produced by the liver. It is an acute phase protein, one whose levels rise in response to inflammation. It assists the binding of complement proteins to foreign or damaged cells, an immunological response that destroys the target cells. High blood levels of CRP are associated with increased risk of heart disease and diabetes.