FunctionCotranslationally removes the N-terminal methionine from nascent proteins. The N-terminal methionine is often cleaved when the second residue in the primary sequence is small and uncharged (Met-Ala-, Cys, Gly, Pro, Ser, Thr, or Val). The catalytic activity of human METAP2 toward Met-Val peptides is consistently two orders of magnitude higher than that of METAP1, suggesting that it is responsible for processing proteins containing N-terminal Met-Val and Met-Thr sequences in vivo. Protects eukaryotic initiation factor EIF2S1 from translation-inhibiting phosphorylation by inhibitory kinases such as EIF2AK2/PKR and EIF2AK1/HCR. Plays a critical role in the regulation of protein synthesis.
Sequence similaritiesBelongs to the peptidase M24A family. Methionine aminopeptidase eukaryotic type 2 subfamily.
Post-translational modificationsContains approximately 12 O-linked N-acetylglucosamine (GlcNAc) residues. O-glycosylation is required for EIF2S1 binding.
Cellular localizationCytoplasm. About 30% of expressed METAP2 associates with polysomes.