PMID- 6742859
OWN - NLM
STAT- MEDLINE
DCOM- 19840816
LR  - 20190629
IS  - 0003-9861 (Print)
IS  - 0003-9861 (Linking)
VI  - 232
IP  - 1
DP  - 1984 Jul
TI  - Rabbit heart mitochondrial hexokinase: solubilization and general properties.
PG  - 391-9
AB  - In rabbit heart, results show that two isoenzymes of hexokinase (HK) are present. 
      The enzymatic activity associated with mitochondria consists of only one 
      isoenzyme; according to its electrophoretic mobility and its apparent Km for 
      glucose (0.065 mM), it has been identified as type I isoenzyme. The bound HK I 
      exhibits a lower apparent Km for ATPMg than the solubilized enzyme, whereas the 
      apparent Km for glucose is the same for bound and solubilized HK. Detailed 
      studies have been performed to investigate the interactions which take place 
      between the enzyme and the mitochondrial membrane. Neutral salts efficiently 
      solubilize the bound enzyme. Digitonin induces only a partial release of the 
      enzyme bound to mitochondria; this result could be explained by the existence of 
      contacts between the outer and the inner mitochondrial membranes [C. R. 
      Hackenbrock (1968) Proc. Natl. Acad. Sci. USA 61, 598-605]. Furthermore, low 
      concentrations (0.1 mM) of glucose 6-phosphate (G6P) or ATP4- specifically 
      solubilize hexokinase. The solubilizing effect of G6P and ATP4-, which are potent 
      inhibitors of the enzyme, can be prevented by incubation of mitochondria with Pi 
      or Mg2+. In addition, enzyme solubilization by G6P can be reversed by Mg2+ only 
      when the proteolytic treatment of the heart homogenate is omitted during the 
      course of the isolation of mitochondria. These results concerning the interaction 
      of rabbit heart hexokinase with the outer mitochondrial membrane agree with the 
      schematic model proposed by Wilson [(1982) Biophys. J. 37, 18-19] for the brain 
      enzyme. This model involves the existence of two kinds of interactions between HK 
      and mitochondria; a very specific one with the hexokinase-binding protein of the 
      outer mitochondrial membrane, which is suppressed by glucose 6-phosphate, and a 
      less specific, cation-mediated one.
FAU - Aubert-Foucher, E
AU  - Aubert-Foucher E
FAU - Font, B
AU  - Font B
FAU - Gautheron, D C
AU  - Gautheron DC
LA  - eng
PT  - Journal Article
PL  - United States
TA  - Arch Biochem Biophys
JT  - Archives of biochemistry and biophysics
JID - 0372430
RN  - 0 (Isoenzymes)
RN  - EC 2.7.1.1 (Hexokinase)
RN  - KOO5CM684H (Digitonin)
SB  - IM
MH  - Animals
MH  - Chemical Phenomena
MH  - Chemistry
MH  - Digitonin
MH  - Hexokinase/*isolation & purification/metabolism
MH  - Isoenzymes/isolation & purification/metabolism
MH  - Kinetics
MH  - Mitochondria, Heart/*enzymology
MH  - Rabbits
MH  - Solubility
EDAT- 1984/07/01 00:00
MHDA- 1984/07/01 00:01
CRDT- 1984/07/01 00:00
PHST- 1984/07/01 00:00 [pubmed]
PHST- 1984/07/01 00:01 [medline]
PHST- 1984/07/01 00:00 [entrez]
AID - 0003-9861(84)90554-X [pii]
AID - 10.1016/0003-9861(84)90554-x [doi]
PST - ppublish
SO  - Arch Biochem Biophys. 1984 Jul;232(1):391-9. doi: 10.1016/0003-9861(84)90554-x.