PROSITE documentation PDOC00575
Methionine aminopeptidase signatures


Methionine aminopeptidase (EC (MAP) is responsible for the removal of the amino-terminal (initiator) methionine from nascent eukaryotic cytosolic and cytoplasmic prokaryotic proteins if the penultimate amino acid is small and uncharged. All MAP studied to date are monomeric proteins that require cobalt ions for activity.

Two subfamilies of MAP enzymes are known to exist [1,2]. While being evolutionary related, they only share a limited amount of sequence similarity mostly clustered around the residues shown, in the Escherichia coli MAP [3], to be involved in cobalt-binding.

The first family consists of enzymes from prokaryotes as well as eukaryotic MAP-1, while the second group is made up of archebacterial MAP and eukaryotic MAP-2. The second subfamily also includes proteins which do not seem to be MAP, but that are clearly evolutionary related such as mouse proliferation-associated protein 1 and fission yeast curved DNA-binding protein.

For each of these subfamilies, we developed a specific signature pattern that includes residues known to be involved in colbalt-binding.


These proteins belong to family M24A and M24C in the classification of peptidases [4,E1].

Last update:

April 2006 / Patterns revised.


Technical section

PROSITE methods (with tools and information) covered by this documentation:

MAP_1, PS00680; Methionine aminopeptidase subfamily 1 signature  (PATTERN)

MAP_2, PS01202; Methionine aminopeptidase subfamily 2 signature  (PATTERN)


1AuthorsArfin S.M. Kendall R.L. Hall L. Weaver L.H. Stewart A.E. Matthews B.W. Bradshaw R.A.
TitleEukaryotic methionyl aminopeptidases: two classes of cobalt-dependent enzymes.
SourceProc. Natl. Acad. Sci. U.S.A. 92:7714-7718(1995).
PubMed ID7644482

2AuthorsKeeling P.J. Doolittle W.F.
TitleMethionine aminopeptidase-1: the MAP of the mitochondrion?
SourceTrends Biochem. Sci. 21:285-286(1996).
PubMed ID8772380

3AuthorsRoderick S.L. Matthews B.W.
TitleStructure of the cobalt-dependent methionine aminopeptidase from Escherichia coli: a new type of proteolytic enzyme.
SourceBiochemistry 32:3907-3912(1993).
PubMed ID8471602

4AuthorsRawlings N.D. Barrett A.J.
TitleEvolutionary families of metallopeptidases.
SourceMethods Enzymol. 248:183-228(1995).
PubMed ID7674922


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