| Literature References | 1. ALBIG, W. AND ENTIAN, K.D.
Structure of yeast glucokinase, a strongly diverged specific aldo-
hexose-phosphorylating isoenzyme.
GENE 73 141-152 (1988).
2. GRIFFIN, L.D., GELB, B.D., WHEELER, D.A., DAVISON, D., ADAMS, V.
AND MCCABE, E.R.
Mammalian hexokinase 1: evolutionary conservation and structure to
function analysis.
GENOMICS 11 1014-1024 (1991).
3. MAGNANI, M., BIANCHI, M., CASABIANCI, A., STOCCHI, V., DANIELE, A.,
ALTRUDA, F., FERRONE, M. AND SILENGO, L.
A recombinant human 'mini'-hexokinase is catalytically active and
regulated by hexose-6-phosphates.
BIOCHEM.J. 285 193-199 (1992).
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| Documentation | Hexokinase is an important enzyme that catalyses the ATP-dependent
conversion of aldo- and keto-hexose sugars to the hexose-6-phosphate [1,2].
The enzyme can catalyse this reaction on glucose, fructose, sorbitol and
glucosamine, and as such is the first step in a number of metabolic
pathways [1].
There are 3 isozymes of hexokinase in yeast (PI, PII and glucokinase):
isozymes PI and PII phosphorylate both aldo- and keto-sugars; glucokinase
is specific for aldo-hexoses [1]. All 3 isozymes contain a single copy of
the hexokinase domain [1,2]. Vertebrates contain 4 hexokinase isozymes
(designated I to IV [2]): types I to III contain 2 repeats of the hexokinase
domain, and are thought to be derived by gene duplication of a yeast
hexokinase that is insensitve to product inhibition [3]. The N-terminal
unit of types I to III is the regulatory- and the C-terminal unit the
catalytic-region [2]. It is believed that a mutation in the N-terminal
ATP-binding domain has caused the loss of the ability to dephosphorylate
ATP, resulting in loss of catalytic activity and the subsequent change to
a regulatory role [2]. However, some studies have suggested the C-terminal
catalytic region may also contain a regulatory site [3]. Type IV hexokinase
contains only one hexokinase domain, and is sometimes incorrectly referred
to as glucokinase.
Structural studies of yeast hexokinase reveal a well-defined catalytic
pocket that binds ATP and hexose, allowing easy transfer of the phosphate
from ATP to the sugar.
HEXOKINASE is a 7-element fingerprint that provides a signature for the
hexokinase family. The fingerprint was derived from an initial alignment
of 7 sequences: the motifs were drawn from conserved regions spanning
virtually the full alignment length, motif 1 encoding the putative ATP-
binding domain, and motif 2 including the sugar-binding region encoded by
PROSITE pattern HEXOKINASES (PS00378). All motifs, except motif 6, contain
amino acids that project into or near the ATP/sugar-binding pocket. Two
iterations on OWL27.0 were required to reach convergence, at which point
a true set comprising 36 sequences was identified.
An update on SPTR37_9f identified a true set of 43 sequences, and 1
partial match.
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| Sequence Titles | HXK1_BOVIN HEXOKINASE, TYPE I (EC 2.7.1.1) (HK I) (BRAIN FORM HEXOKINASE) - BOS TAURUS (BOVINE).
HXK1_HUMAN HEXOKINASE, TYPE I (EC 2.7.1.1) (HK I) (BRAIN FORM HEXOKINASE) - HOMO SAPIENS (HUMAN).
HXK1_MOUSE HEXOKINASE, TYPE I (EC 2.7.1.1) (HK I) (HEXOKINASE, TUMOR ISOZYME) - MUS MUSCULUS (MOUSE).
HXK1_RAT HEXOKINASE, TYPE I (EC 2.7.1.1) (HK I) (BRAIN FORM HEXOKINASE) - RATTUS NORVEGICUS (RAT).
HXK1_SCHPO HEXOKINASE 1 (EC 2.7.1.1) - SCHIZOSACCHAROMYCES POMBE (FISSION YEAST).
HXK2_HUMAN HEXOKINASE, TYPE II (EC 2.7.1.1) (HK II) - HOMO SAPIENS (HUMAN).
HXK2_MOUSE HEXOKINASE TYPE II (EC 2.7.1.1) (HK II) - MUS MUSCULUS (MOUSE).
HXK2_RAT HEXOKINASE TYPE II (EC 2.7.1.1) (HK II) - RATTUS NORVEGICUS (RAT).
HXK2_SCHPO HEXOKINASE 2 (EC 2.7.1.1) - SCHIZOSACCHAROMYCES POMBE (FISSION YEAST).
HXK3_HUMAN HEXOKINASE TYPE III (EC 2.7.1.1) (HK III) - HOMO SAPIENS (HUMAN).
HXK3_RAT HEXOKINASE TYPE III (EC 2.7.1.1) (HK III) - RATTUS NORVEGICUS (RAT).
HXKA_YEAST HEXOKINASE A (EC 2.7.1.1) (HEXOKINASE PI) - SACCHAROMYCES CEREVISIAE (BAKER'S YEAST).
HXKB_YEAST HEXOKINASE B (EC 2.7.1.1) (HEXOKINASE PII) - SACCHAROMYCES CEREVISIAE (BAKER'S YEAST).
HXKG_ASPNG GLUCOKINASE (EC 2.7.1.2) (GLUCOSE KINASE) (GLK) - ASPERGILLUS NIGER.
HXKG_YEAST GLUCOKINASE (EC 2.7.1.2) (GLUCOSE KINASE) (GLK) - SACCHAROMYCES CEREVISIAE (BAKER'S YEAST).
HXKH_HUMAN HEXOKINASE D, LIVER ISOZYMES (EC 2.7.1.1) (HEXOKINASE TYPE IV) (HK4) (GLUCOKINASE) - HOMO SAPIENS (HUMAN).
HXKH_MOUSE HEXOKINASE D, HEPATIC ISOZYME (EC 2.7.1.1) (HEXOKINASE TYPE IV) (HK4) (GLUCOKINASE) - MUS MUSCULUS (MOUSE).
HXKH_RAT HEXOKINASE D, HEPATIC ISOZYME (EC 2.7.1.1) (HEXOKINASE TYPE IV) (HK4) (GLUCOKINASE) - RATTUS NORVEGICUS (RAT).
HXKP_HUMAN HEXOKINASE D, PANCREATIC ISOZYME (EC 2.7.1.1) (HEXOKINASE TYPE IV) (HK4) (GLUCOKINASE) - HOMO SAPIENS (HUMAN).
HXKP_MOUSE HEXOKINASE D, PANCREATIC ISOZYME (EC 2.7.1.1) (HEXOKINASE TYPE IV) (HK4) (GLUCOKINASE) - MUS MUSCULUS (MOUSE).
HXKP_RAT HEXOKINASE D, PANCREATIC ISOZYMES (EC 2.7.1.1) (HEXOKINASE TYPE IV) (HK4) (GLUCOKINASE) - RATTUS NORVEGICUS (RAT).
HXK_ARATH HEXOKINASE (EC 2.7.1.1) - ARABIDOPSIS THALIANA (MOUSE-EAR CRESS).
HXK_DEBOC HEXOKINASE (EC 2.7.1.1) - DEBARYOMYCES OCCIDENTALIS (YEAST) (SCHWANNIOMYCES OCCIDENTALIS).
HXK_KLULA HEXOKINASE (EC 2.7.1.1) - KLUYVEROMYCES LACTIS (YEAST).
HXK_PLAFA HEXOKINASE (EC 2.7.1.1) - PLASMODIUM FALCIPARUM.
HXK_SCHMA HEXOKINASE (EC 2.7.1.1) - SCHISTOSOMA MANSONI (BLOOD FLUKE).
O09487 HEXOKINASE (EC 2.7.1.1) (GLUCOKINASE) (HEXOKINASE TYPE IV) - ENTAMOEBA DISPAR.
O09488 HEXOKINASE (EC 2.7.1.1) (GLUCOKINASE) (HEXOKINASE TYPE IV) - ENTAMOEBA DISPAR.
O43443 HEXOKINASE I (EC 2.7.7.1) (NICOTINAMIDE-NUCLEOTIDE ADENYLYLTRANSFERASE) (NAD(+) PYROPHOSPHORYLASE) - HOMO SAPIENS (HUMAN).
O43444 HEXOKINASE I (EC 2.7.7.1) (NICOTINAMIDE-NUCLEOTIDE ADENYLYLTRANSFERASE) (NAD(+) PYROPHOSPHORYLASE) - HOMO SAPIENS (HUMAN).
O54892 MUTANT TYPE II HEXOKINASE - RATTUS NORVEGICUS (RAT).
O64390 HEXOKINASE - SOLANUM TUBEROSUM (POTATO).
O74996 HEXOKINASE - YARROWIA LIPOLYTICA (CANDIDA LIPOLYTICA).
P93834 HEXOKINASE 2 (EC 2.7.1.1) (GLUCOKINASE) (HEXOKINASE TYPE IV) - ARABIDOPSIS THALIANA (MOUSE-EAR CRESS).
Q04409 D9719.21P - SACCHAROMYCES CEREVISIAE (BAKER'S YEAST).
Q05838 HEXOKINASE PI (HXK2) - SACCHAROMYCES CEREVISIAE (BAKER'S YEAST).
Q19440 F14B4.2 PROTEIN - CAENORHABDITIS ELEGANS.
Q27647 HEXOKINASE (EC 2.7.1.1) (GLUCOKINASE) (HEXOKINASE TYPE IV) - ENTAMOEBA HISTOLYTICA.
Q27648 HEXOKINASE (EC 2.7.1.1) (GLUCOKINASE) (HEXOKINASE TYPE IV) - ENTAMOEBA HISTOLYTICA.
Q42535 HEXOKINASE 1 (EC 2.7.1.1) (GLUCOKINASE) (HEXOKINASE TYPE IV) - ARABIDOPSIS THALIANA (MOUSE-EAR CRESS).
Q64476 HEXOKINASE (EC 2.7.1.1) - MUS MUSCULUS (MOUSE).
Q64596 RAT GLUCOKINASE, ALTERNATIVELY SPLICED GK3 (EC 2.7.1.1) (HEXOKINASE) (HEXOKINASE TYPE IV) (HEXOKINASE TYPE 4) - RATTUS NORVEGICUS (RAT).
Q91753 GLUCOKINASE - XENOPUS LAEVIS (AFRICAN CLAWED FROG).
O83518 HEXOKINASE (HXK) - TREPONEMA PALLIDUM.
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