MetaCyc Reaction:

Superclasses: Reactions Classified By Conversion TypeSimple ReactionsChemical Reactions
Reactions Classified By SubstrateSmall-Molecule Reactions

EC Number:

Enzymes and Genes:

Bifidobacterium longum: N-acetylhexosamine kinaseInferred from experiment: lnpB

The direction shown, i.e. which substrates are on the left and right sides, is in accordance with the Enzyme Commission system.

Most BioCyc compounds have been protonated to a reference pH value of 7.3. Please see the PGDB Concepts Guide for more information.

Mass balance status: Balanced.

Instance reaction:
ATP + N-acetyl-α-D-galactosamine = ADP + N-acetyl-α-D-galactosamine 1-phosphate + H+ (

Enzyme Commission Primary Name: N-acetylhexosamine 1-kinase

Enzyme Commission Synonyms: NahK, LnpB, N-acetylgalactosamine/N-acetylglucosamine 1-kinase

Taxonomic Range: Bacteria

Standard Gibbs Free Energy (ΔrG in kcal/mol): -14.815857Inferred by computational analysis [Latendresse13]

Enzyme Commission Summary:
Differs from EC, N-acetylgalactosamine kinase, as it can phosphorylate both N-acetyl-α-D-galactosamine and N-acetyl-β-D-glucosamine at similar rates. Also has some activity with N-acetyl-β-D-mannosamine, D-talose and D-mannose as substrate. ATP can be replaced by GTP or ITP but with decreased enzyme activity. Requires a divalent cation, with Mg2+ resulting in by far the greatest stimulation of enzyme activity [Nishimoto07].

Gene-Reaction Schematic

Gene-Reaction Schematic

Instance reaction of [an N-acetyl-D-hexosamine + ATP = an N-acetyl-α-D-hexosamine 1-phosphate + ADP + H+] (
i1: ATP + N-acetyl-α-D-galactosamine = ADP + N-acetyl-α-D-galactosamine 1-phosphate + H+ (

Unification Links: KEGG:R08962, Rhea:25428

Relationship Links: BRENDA:EC:, ENZYME:EC:, IUBMB-ExplorEnz:EC:


Latendresse13: Latendresse M. (2013). "Computing Gibbs Free Energy of Compounds and Reactions in MetaCyc."

Nishimoto07: Nishimoto M, Kitaoka M (2007). "Identification of N-acetylhexosamine 1-kinase in the complete lacto-N-biose I/galacto-N-biose metabolic pathway in Bifidobacterium longum." Appl Environ Microbiol 73(20);6444-9. PMID: 17720833

Report Errors or Provide Feedback
Please cite the following article in publications resulting from the use of MetaCyc: Caspi et al, Nucleic Acids Research 42:D459-D471 2014
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