Hepatic fructokinase

ketohexokinase (fructokinase)
Ketohexokinase homodimer, Human
Identifiers
Symbol	KHK
NCBI gene	3795
HGNC	6315
OMIM	229800
RefSeq	NM_006488
UniProt	P50053
Other data
EC number	2.7.1.3
Locus	Chr. 2 p23.3-23.2
Search for Structures Swiss-model Domains InterPro

Ketohexokinase
Identifiers
EC no.	2.7.1.3
CAS no.	9030-50-6
Databases
IntEnz	IntEnz view
BRENDA	BRENDA entry
ExPASy	NiceZyme view
KEGG	KEGG entry
MetaCyc	metabolic pathway
PRIAM	profile
PDB structures	RCSB PDB PDBe PDBsum
Search PMC articles PubMed articles NCBI proteins

Hepatic fructokinase (or ketohexokinase) is an enzyme that catalyzes the phosphorylation of fructose to produce fructose-1-phosphate.

ATP +  ${\displaystyle \longrightarrow }$ ADP +

ATP + D-fructose → ADP + D-fructose-1-phosphate ^[1]

Isoforms

In humans, ketohexokinase is encoded by the KHK gene, which produces two isoforms, KHK-A and KHK-C, through alternative splicing.

• KHK-C is primarily expressed in the liver, kidney, and intestine. It has a high affinity for fructose (low K_m) and is responsible for the majority of fructose metabolism.
• KHK-A is ubiquitously expressed in many tissues at low levels. It has a significantly lower affinity for fructose (high K_m) compared to the C isoform. ^[2]

References

1. Bais R, James HM, Rofe AM, Conyers RA (1985). "The purification and properties of human liver ketohexokinase. A role for ketohexokinase and fructose-bisphosphate aldolase in the metabolic production of oxalate from xylitol". Biochem. J. 230 (1): 53–60. doi:10.1042/bj2300053. PMC   1152585 . PMID   2996495.
2. Diggle CP, Shires M, Leitch D, Brooke D, Carr IM, Markham AF, Hayward BE, Asipu A, Bonthron DT (2009). "Ketohexokinase: Expression and Localization of the Principal Fructose-metabolizing Enzyme". Journal of Histochemistry & Cytochemistry. 57 (8): 763–774. doi:10.1369/jhc.2009.953190. PMC   2713076 . PMID   19365088.

External links

• Hepatic+fructokinase at the U.S. National Library of Medicine Medical Subject Headings (MeSH)