The pathway of anaerobic glycolysis of Trypanosoma brucei has been studied
by the following five approaches :
1. Ensyme activity required for the various different postulated schemes for
anaerobic glycolysis (hexose monophosphate aldolase, glycerol
dehydrogenase, glycerophosphate : glucose or glycerophosphate : fructosesphosphate
or glycerophosphate : triose or* glycerophosphate : ALP
transphosphorylases) have been examined in a variety of assay conditions.
Only significant activities of glycerophosphate : ALP transphosphorylase
were detectable.
2. Broken cell incubation studies established that there were no significant
differences in the sequence of the increase and decrease in glycolytic
intermediates between aerobic and anaerobic pathways.3. Whole cell adenylate charge and glycolytic intermediates were assayed in
steady-state aerobic, anaerobic and in the transitions between aerobic to
anaerobic, and anaerobic to aerobic showed glucose-6-phosj)hate production
to be the rate limiting step in anaerobic glucose utilization.
Salicylhyaroxamic acid (0.5 mM) inhibited only glycerophosphate oxidase -and
so simulated anaerobiosis.
4. The inhibitory effect of glycerol on whole cells metabolising glucose
anaerobically showed it to be dependent upon the intracellular
concentration of glycerophosphate. Consequently its inhibitory effect
is not caused through the inhibition of glucose transport.
5. The concentration of glycerophosphate in cells metabolising glucose under
glycerophosphate oxidase inhibited conditions was found to increase rapidly
to a concentration that was independent of time and extracellular glycerol
concentration. Furthermore it was found to be an intermediate in
anaerobic glucose utilization.
The results of this work were consistent with the pathway of carbohydrate
metabolism under glycerophosphate oxidase inhibition which involved the
production of glycerol plus ATP from ADP plus glycerophosphate catalysed by
glycerokinase
