PROSITE documentation PDOC00894
Glucosamine/galactosamine-6-phosphate isomerases signature


Glucosamine-6-phosphate isomerase (EC (or Glc-6-P deaminase) is the enzyme responsible for the conversion of glucosamine 6-phosphate into fructose 6 phosphate [1]. It is the last specific step in the pathway for N-acetylglucosamine (GlcNAC) utilization in bacteria such as Escherichia coli (gene nagB) or in fungi such as Candida albicans (gene NAG1).

Glc-6-P isomerase is evolutionary related to:

  • A putative Escherichia coli galactosamine-6-phosphate isomerase (gene agaI) [2].
  • Escherichia coli hypothetical protein yieK.
  • Bacillus subtilis hypothetical protein ybfT.

As a signature pattern we selected a conserved region located in the central part of these enzymes. This region contains a conserved histidine which has been shown [1], in nagB, to be important for the pyranose ring-opening step of the catalytic mechanism.

Last update:

December 2004 / Pattern and text revised.


Technical section

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

GLC_GALNAC_ISOMERASE, PS01161; Glucosamine/galactosamine-6-phosphate isomerases signature  (PATTERN)


1AuthorsOliva G. Fontes M.R.M. Garratt R.C. Altamirano M.M. Calcagno M.L. Horjales E.
TitleStructure and catalytic mechanism of glucosamine 6-phosphate deaminase from Escherichia coli at 2.1 A resolution.
SourceStructure 3:1323-1332(1995).
PubMed ID8747459

2AuthorsReizer J. Ramseier T.M. Reizer A. Charbit A. Saier M.H. Jr.
TitleNovel phosphotransferase genes revealed by bacterial genome sequencing: a gene cluster encoding a putative N-acetylgalactosamine metabolic pathway in Escherichia coli.
SourceMicrobiology 142:231-250(1996).
PubMed ID8932697

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