PMID- 2942109
OWN - NLM
STAT- MEDLINE
DCOM- 19860820
LR  - 20190628
IS  - 0003-9861 (Print)
IS  - 0003-9861 (Linking)
VI  - 248
IP  - 1
DP  - 1986 Jul
TI  - An examination of the in vivo distribution of brain hexokinase between the 
      cytosol and the outer mitochondrial membrane.
PG  - 253-71
AB  - These studies addressed the question of the in vivo distribution of rat brain 
      hexokinase (HK), and whether physiologically relevant changes in the glycolytic 
      rate are accompanied by changes in the distribution of HK. Homogenates of fresh 
      tissue showed only 11-15% of the overt (assayable without added detergent) HK to 
      be soluble (found in high-speed centrifugation supernatant fractions) when 
      homogenization was begun within 15-20 s of sacrifice. Freeze-blown rat brain 
      tissue also was used, coupled with a new technique wherein it was homogenized as 
      it thawed in a buffered sucrose solution containing 1 mM EDTA. In tissue sampled 
      15 min (anesthetized) or 60 min (waking) after ip Nembutal injection (40 mg/kg), 
      23% of the overt HK and 79% of the total lactate dehydrogenase were soluble. The 
      average phosphocreatine content of these and similar homogenates had decreased 
      only 23% from in vivo levels, while ATP had decreased by 65%, due to the combined 
      effects of a high level of endogenous ATPase, chelation of Mg2+ by EDTA, and the 
      greater stability of Mg-ATP2- relative to Mg-ADP1-. These data indicated that the 
      tissue experienced, at most, the equivalent of 6 s of complete ischemia prior to 
      the completion of homogenization. Synaptosomes derived from rat and chicken 
      cerebra were incubated at 37 degrees C in a physiological salt solution 
      containing 10 mM glucose. Addition of veratridine has been shown to stimulate 
      glycolysis and oxidative phosphorylation two- to threefold (H. T. Kyriazi and R. 
      E. Basford (1986) J. Neurochem., in press), but did not alter the HK 
      distribution, as 21% was found in the supernatant fractions of both control and 
      veratridine-stimulated synaptosomes treated with digitonin. These results 
      indicate that in brain tissue, large net movements of HK on and off the outer 
      mitochondrial membrane do not occur, and thus play no role in the regulation of 
      glycolysis.
FAU - Kyriazi, H T
AU  - Kyriazi HT
FAU - Basford, R E
AU  - Basford RE
LA  - eng
GR  - NS-11773/NS/NINDS NIH HHS/United States
PT  - Comparative Study
PT  - Journal Article
PT  - Research Support, U.S. Gov't, P.H.S.
PL  - United States
TA  - Arch Biochem Biophys
JT  - Archives of biochemistry and biophysics
JID - 0372430
RN  - 020IUV4N33 (Phosphocreatine)
RN  - 8L70Q75FXE (Adenosine Triphosphate)
RN  - 9G34HU7RV0 (Edetic Acid)
RN  - EC 1.1.1.27 (L-Lactate Dehydrogenase)
RN  - EC 2.7.1.1 (Hexokinase)
RN  - EC 2.7.1.11 (Phosphofructokinase-1)
RN  - EC 3.6.1.- (Adenosine Triphosphatases)
RN  - KOO5CM684H (Digitonin)
SB  - IM
MH  - Adenosine Triphosphatases/metabolism
MH  - Adenosine Triphosphate/metabolism
MH  - Aging
MH  - Animals
MH  - Brain/*enzymology
MH  - Cytosol/*enzymology
MH  - Digitonin/pharmacology
MH  - Edetic Acid/pharmacology
MH  - Glycolysis
MH  - Hexokinase/*metabolism
MH  - Intracellular Membranes/enzymology
MH  - L-Lactate Dehydrogenase/metabolism
MH  - Mice
MH  - Mitochondria/*enzymology
MH  - Phosphocreatine/metabolism
MH  - Phosphofructokinase-1/metabolism
MH  - Rats
MH  - Synaptic Membranes/drug effects
MH  - Synaptosomes/enzymology
EDAT- 1986/07/01 00:00
MHDA- 1986/07/01 00:01
CRDT- 1986/07/01 00:00
PHST- 1986/07/01 00:00 [pubmed]
PHST- 1986/07/01 00:01 [medline]
PHST- 1986/07/01 00:00 [entrez]
AID - 0003-9861(86)90423-6 [pii]
AID - 10.1016/0003-9861(86)90423-6 [doi]
PST - ppublish
SO  - Arch Biochem Biophys. 1986 Jul;248(1):253-71. doi: 10.1016/0003-9861(86)90423-6.