Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Pivot Concepts:
Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Target Concepts:
Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Query: EC:2.3.1.28 (
chloramphenicol acetyltransferase
)
5,100
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
The proportion of hexokinase (HK; EC 2.7.1.1) isozyme 1 (
HK1
) that is bound to the outer mitochondrial membrane is tissue specific and developmentally regulated. HK activity is known to be markedly elevated in many cancer cells and a significant fraction is mitochondrial bound. This study examined the role of the 15-amino acid N-terminal domain of
HK1
in binding to liver and hepatoma mitochondria. A chimeric reporter construct, pCMVHKCAT, encoding this
HK1
domain coupled to the
chloramphenicol acetyltransferase
(
CAT
) gene was electroporated into mouse Hepa 1-6 hepatoma cells. After digitonin treatment, cell fractions were assayed for HK, lactate dehydrogenase, and
CAT
activities. Digitonin (75 micrograms/mg of protein) caused cytosolic leak but 70% of HK remained with the pellet. HKCAT, like HK, remained predominantly with the pellet;
CAT
form the control, pCMVCAT, remained mostly unbound. Binding of membrane-free cell extracts to rat liver mitochondria in vitro showed 91% of the HKCAT bound, whereas only 12% of
CAT
bound. Specificity of HKCAT binding to mitochondria was demonstrated by competition of
HK1
for HKCAT binding sites on rat liver mitochondria as well as by blockage of HKCAT binding by N,N'-dicyclohexylcarbodiimide, which covalently binds to porin and blocks
HK1
binding. Deletional mutant constructs of HKCAT showed reduced binding with increasing deletion size. In summary, these studies demonstrate that the 15-amino acid N-terminal domain of
HK1
is necessary and sufficient to confer mitochondrial binding properties to
CAT
and that there is specificity for this binding to the mitochondria.
...
PMID:Targeting of hexokinase 1 to liver and hepatoma mitochondria. 130 5
