AJP - Regulatory, Integrative and Comparative Physiology, Vol 262, Issue 3 517-R523, Copyright © 1992 by American Physiological Society
Subcellular enzyme binding and the regulation of glycolysis in anoxic turtle brain
J. A. Duncan and K. B. Storey
Institute of Biochemistry, Carleton University, Ottawa, Ontario, Canada.
The association of glycolytic enzymes with the particulate fraction of the
cell was assessed in the brain of the freshwater turtle, Pseudemys scripta
elegans, using three different methodologies. Each method showed that a
large percentage of each of eight enzymes was bound in brain. The effect of
environmental anoxia (5 or 20 h submergence in N2-bubbled water at 7
degrees C) on the distribution of enzymes between free and bound states was
analyzed. All three techniques showed a significant increase in the
percentages of brain aldolase and glyceraldehyde-3-phosphate dehydrogenase
bound during anoxia and no change in lactate dehydrogenase or creatine
kinase binding. Two methodologies also showed an increase in the percent
bound during anoxia for hexokinase, phosphofructokinase, and
phosphoglycerate kinase. An increased association of glycolytic enzymes
with structural elements of the cell during anoxia may physically position
the glycolytic pathway to facilitate coupling between this ATP-generating
pathway and ATP-utilizing processes, such as membrane ion pumps.
