A phosphoprotein is a protein that is posttranslationally modified by the attachment of either a single phosphate group, or a complex molecule such as 5'-phospho-DNA, through a phosphate group.
The target amino acid is most often serine, threonine, or tyrosine residues (mostly in eukaryotes), or aspartic acid or histidine residues (mostly in prokaryotes).
[1] The phosphorylation of proteins is a major regulatory mechanism in cells.
[2][3] Phosphoproteins have been proposed as biomarkers for breast cancer.
This protein-related article is a stub.