To improve security and privacy, we are moving our web pages and services from HTTP to HTTPS.
To give users of web services time to transition to HTTPS, we will support separate HTTP and HTTPS services until the end of 2017.
From January 2018 most HTTP traffic will be automatically redirected to HTTPS. [more...]
View this page in https
PROSITE documentation PDOC00746 [for PROSITE entry PS00965]

Phosphomannose isomerase type I signatures


Phosphomannose isomerase (EC (PMI) [1,2] is the enzyme that catalyzes the interconversion of mannose-6-phosphate and fructose-6-phosphate. In eukaryotes, it is involved in the synthesis of GDP-mannose which is a constituent of N- and O-linked glycans as well as GPI anchors. In prokaryotes, it is involved in a variety of pathways including capsular polysaccharide biosynthesis and D-mannose metabolism.

Three classes of PMI have been defined on the basis of sequence similarities [1]. The first class comprises all known eukaryotic PMI as well as the enzyme encoded by the manA gene in enterobacteria such as Escherichia coli. Class I PMI's are proteins of about 42 to 50 Kd which bind a zinc ion essential for their activity.

As signature patterns for class I PMI, we selected two conserved regions. The first one is located in the N-terminal section of these proteins, the second in the C-terminal half. Both patterns contain a residue involved [3] in the binding of the zinc ion.

Expert(s) to contact by email:

Proudfoot A.E.I.

Last update:

November 1997 / Text revised.

Technical section

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

PMI_I_1, PS00965; Phosphomannose isomerase type I signature 1  (PATTERN)

PMI_I_2, PS00966; Phosphomannose isomerase type I signature 2  (PATTERN)


1AuthorsProudfoot A.E.I., Turcatti G., Wells T.N., Payton M.A., Smith D.J.
TitlePurification, cDNA cloning and heterologous expression of human phosphomannose isomerase.
SourceEur. J. Biochem. 219:415-423(1994).
PubMed ID8307007

2AuthorsCoulin F., Magnenat E., Proudfoot A.E.I., Payton M.A., Scully P., Wells T.N.C.
TitleIdentification of Cys-150 in the active site of phosphomannose isomerase from Candida albicans.
SourceBiochemistry 32:14139-14144(1993).
PubMed ID8260497

3AuthorsCleasby A., Wonacott A., Skarzynski T., Hubbard R.E., Davies G.J., Proudfoot A.E.I., Bernard A.R., Payton M.A., Wells T.N.C.
TitleThe x-ray crystal structure of phosphomannose isomerase from Candida albicans at 1.7 angstrom resolution.
SourceNat. Struct. Biol. 3:470-479(1996).
PubMed ID8612079

PROSITE is copyright. It is produced by the SIB Swiss Institute Bioinformatics. There are no restrictions on its use by non-profit institutions as long as its content is in no way modified. Usage by and for commercial entities requires a license agreement. For information about the licensing scheme send an email to
Prosite License or see: prosite_license.html.


View entry in original PROSITE document format
View entry in raw text format (no links)