General term for a protein without its characteristic prosthetic group, which may be a metal or a small organic compound; for example, the protein apotransferrin combines with iron to form transferrin, and protein apoceruloplasmin combines with copper to form the enzyme ceruloplasmin.

The protein components of a number of complexes, such as Enzymes (Apoenzymes), Ferritin (Apoferritins), or Lipoproteins (Apolipoproteins).

A large and highly glycosylated protein constituent of Lipoprotein (a). It has very little affinity for Lipids but Forms disulfide-linkage to Apolipoprotein B-100. Apoprotein(a) has Serine Proteinase [..]

The protein component of a conjugated protein.

<protein> A term used to describe a protein that is normally attached to second molecule that is not a polypeptide, from which it has become disassociated. For example: ferritin that lacks the ferric hydroxide core could be called apoferritin. (18 Nov 2007)