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Reviewed, UniProtKB/Swiss-Prot P50053 (KHK_HUMAN)

Last modified November 25, 2008. Version 82. Feed History...

Clusters with 100%, 90%, 50% identity | Documents (7) | Third-party data | Customize display text xml rdf/xml gff fasta
Names and origin · Protein attributes · General annotation (Comments) · Ontologies · Binary interactions · Alternative products · Sequence annotation (Features) · Sequences · References · Cross-references · Entry information · Relevant documents

Names and origin

Protein namesRecommended name:
    Ketohexokinase
    EC=2.7.1.3
Alternative name(s):
    Hepatic fructokinase
Gene names
Name: KHK
OrganismHomo sapiens (Human)
Taxonomic identifier9606 [NCBI]
Taxonomic lineageEukaryotaMetazoaChordataCraniataVertebrataEuteleostomiMammaliaEutheriaEuarchontogliresPrimatesHaplorrhiniCatarrhiniHominidaeHomo

Protein attributes

Sequence length298 AA.
Sequence statusComplete.
Sequence processingThe displayed sequence is not processed.
Protein existenceEvidence at protein level.

General annotation (Comments)

Catalytic activity

ATP + D-fructose = ADP + D-fructose 1-phosphate.

Enzyme regulation

Requires potassium. Inhibition by ADP.

Pathway

Carbohydrate metabolism; fructose metabolism.

Subunit structure

Dimer of A-A, A-C or C-C Probable.

Tissue specificity

Most abundant in liver, kidney, gut, spleen and pancreas. Low levels also found in adrenal, muscle, brain and eye.

Involvement in disease

Defects in KHK are the cause of fructosuria [MIM:229800]. Fructosuria is a benign defect of intermediary metabolism.

Sequence similarities

Belongs to the carbohydrate kinase pfkB family.

Caution

Form C has not yet been fully sequenced in its N-terminal (from 1-69).

Ontologies

Keywords

   Biological processCarbohydrate metabolism
   Coding sequence diversityAlternative splicing
Polymorphism
   DiseaseDisease mutation
   Molecular functionKinase
Transferase
   PTMPhosphoprotein
   Technical term3D-structure

Gene Ontology (GO)

   Biological processcarbohydrate metabolic process

Inferred from electronic annotation. Source: UniProtKB-KW

   Cellular componentcytoplasm

Inferred from direct assay. Source: HPA

   Molecular functionketohexokinase activity Ref.1

Traceable author statement. Source: ProtInc

protein binding

Inferred from physical interaction. Source: IntAct

Complete GO annotation...

Alternative products

This entry describes 2 isoforms produced by alternative splicing. [Align] [Select]
Isoform A (identifier: P50053-1)

This isoform has been chosen as the 'canonical' sequence. All positional information in this entry refers to it. This is also the sequence that appears in the downloadable versions of the entry.
Isoform C (identifier: P50053-2)

The sequence of this isoform differs from the canonical sequence as follows:
     72-115: VLDDLRRYSV...GSRTILYYDR → LVADFRRRGV...GNRTIVLHDT

Sequence annotation (Features)

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifier

Molecule processing

Chain1 – 298298Ketohexokinase
PRO_0000080088

Amino acid modifications

Modified residue1691Phosphoserine By similarity

Natural variations

Alternative sequence72 – 11544VLDDL…LYYDR → LVADFRRRGVDVSQVAWQSK GDTPSSCCIINNSNGNRTIV LHDT in isoform C.
VSP_004669
Natural variant401G → R in fructosuria.
VAR_006072
Natural variant431A → T in fructosuria.
VAR_006073
Natural variant491V → I: dbSNP rs2304681.
VAR_006074
Natural variant1591R → G Either a polymorphism or a cloning artifact.
VAR_006075

Sequences

Sequence LengthMass (Da)Tools
Isoform A [UniParc].

Last modified October 1, 1996. Version 1.
Checksum: 1BA47BDC60C1B89F

FASTA29832,730
        10         20         30         40         50         60 
MEEKQILCVG LVVLDVISLV DKYPKEDSEI RCLSQRWQRG GNASNSCTVL SLLGAPCAFM 

        70         80         90        100        110        120 
GSMAPGHVAD FVLDDLRRYS VDLRYTVFQT TGSVPIATVI INEASGSRTI LYYDRSLPDV 

       130        140        150        160        170        180 
SATDFEKVDL TQFKWIHIEG RNASEQVKML QRIDAHNTRQ PPEQKIRVSV EVEKPREELF 

       190        200        210        220        230        240 
QLFGYGDVVF VSKDVAKHLG FQSAEEALRG LYGRVRKGAV LVCAWAEEGA DALGPDGKLL 

       250        260        270        280        290 
HSDAFPPPRV VDTLGAGDTF NASVIFSLSQ GRSVQEALRF GCQVAGKKCG LQGFDGIV 

« Hide

Isoform C [UniParc].

Checksum: BE77FC325CAC5721
Show »

29832,523

References

« Hide 'large scale' references
[1]"Molecular basis of essential fructosuria: molecular cloning and mutational analysis of human ketohexokinase (fructokinase)."
Bonthron D.T., Brady N., Donaldson I.A., Steinmann B.
Hum. Mol. Genet. 3:1627-1631(1994) [PubMed: 7833921] [Abstract]
Cited for: NUCLEOTIDE SEQUENCE [MRNA], VARIANTS FRUCTOSURIA ARG-40 AND THR-43, VARIANT ILE-49.
[2]"The status, quality, and expansion of the NIH full-length cDNA project: the Mammalian Gene Collection (MGC)."
The MGC Project Team
Genome Res. 14:2121-2127(2004) [PubMed: 15489334] [Abstract]
Cited for: NUCLEOTIDE SEQUENCE [LARGE SCALE MRNA].
Tissue: Lung.
[3]"Structure and alternative splicing of the ketohexokinase gene."
Hayward B.E., Bonthron D.T.
Eur. J. Biochem. 257:85-91(1998) [PubMed: 9799106] [Abstract]
Cited for: NUCLEOTIDE SEQUENCE [GENOMIC DNA] OF 1-26 AND 71-298, ALTERNATIVE SPLICING.
+Additional computationally mapped references.

Cross-references

Sequence databases

X78678 mRNA. Translation: CAA55347.1.
X78677 mRNA. Translation: CAA55346.1.
BC006233 mRNA. Translation: AAH06233.1.
Y09336 Genomic DNA. Translation: CAA70516.1.
Y09341 Genomic DNA. Translation: CAA70522.1.
Y09341 Genomic DNA. Translation: CAA70523.1.
Y09340 Genomic DNA. Translation: CAA70521.1.
AJ005168 Genomic DNA. Translation: CAA06409.1.
RefSeqNP_000212.1.
NP_006479.1.
UniGeneHs.567297

3D structure databases

EntryMethodResolution (Å)ChainPositionsPDBsum
2HLZX-ray1.85A/B/C/D5-298[»]
2HQQX-ray1.86A1-298[»]
2HW1X-ray2.10A1-298[»]
SMRP50053. Positions 5-298.
ModBaseSearch...

Protein-protein interaction databases

IntActP50053.

PTM databases

PhosphoSiteP50053.

2-D gel databases

REPRODUCTION-2DPAGEIPI00029488.

Genome annotation databases

EnsemblENSG00000138030. Homo sapiens. [Contig view]
GeneID3795.
KEGGhsa:3795.

Organism-specific databases

H-InvDBHIX0001908.
HGNCHGNC:6315. KHK.
HPAHPA007040.
MIM229800. gene+phenotype.
Orphanet2056. Fructosuria.
PharmGKBPA30095.
GenAtlasSearch...
GeneCardsSearch...

Phylogenomic databases

HOGENOMP50053.
HOVERGENP50053.

Enzyme and pathway databases

ReactomeREACT_1709. Metabolism of small molecules.

Gene expression databases

CleanExHS_KHK.
GermOnlineENSG00000138030. Homo sapiens.

Family and domain databases

InterProIPR011611. Carb/pur_kinase.
IPR002173. Carboh/pur_kinase_PfkB_CS.
[Graphical view]
PfamPF00294. PfkB. 2 hits.
[Graphical view]
PROSITEPS00583. PFKB_KINASES_1. False negative.
PS00584. PFKB_KINASES_2. False negative.
[Graphical view]
ProtoNetSearch...

Other Resources

NextBio14897.
SOURCESearch...

Entry information

Entry nameKHK_HUMAN
AccessionPrimary (citable) accession number: P50053
Secondary accession number(s): Q99532, Q9BRJ3, Q9UMN1
Entry history
Integrated into UniProtKB/Swiss-Prot: October 1, 1996
Last sequence update: October 1, 1996
Last modified: November 25, 2008
This is version 82 of the entry and version 1 of the sequence. [Complete history]
Entry statusReviewed (UniProtKB/Swiss-Prot)
Annotation projectHPI (Human Proteome Initiative)

Relevant documents

Human chromosome 2

Human chromosome 2: entries, gene names and cross-references to MIM

Human entries with polymorphisms or disease mutations

List of human entries with polymorphisms or disease mutations

Human polymorphisms and disease mutations

Index of human polymorphisms and disease mutations

MIM cross-references

Online Mendelian Inheritance in Man (MIM) cross-references in UniProtKB/Swiss-Prot

PATHWAY comments

Index of metabolic and biosynthesis pathways

PDB cross-references

Index of Protein Data Bank (PDB) cross-references

SIMILARITY comments

Index of protein domains and families

Names and origin · Protein attributes · General annotation (Comments) · Ontologies · Binary interactions · Alternative products · Sequence annotation (Features) · Sequences · References · Cross-references · Entry information · Relevant documents