posted on 2021-05-27, 01:12authored byPureun Kim, Changbong Hyeon
Temporal order in living matters
reflects the self-organizing nature
of dynamical processes driven out of thermodynamic equilibrium. Because
of functional reasons, the period of a biochemical oscillation must
be tuned to a specific value with precision; however, according to
the thermodynamic uncertainty relation (TUR), the precision of the
oscillatory period is constrained by the thermodynamic cost of generating
it. After reviewing the basics of chemical oscillations using the
Brusselator as a model system, we study the glycolytic oscillation
generated by octameric phosphofructokinase (PFK), which is known to
display a period of several minutes. By exploring the phase space
of glycolytic oscillations, we find that the glycolytic oscillation
under the cellular condition is realized in a cost-effective manner.
Specifically, over the biologically relevant range of parameter values
of glycolysis and octameric PFK, the entropy production from the glycolytic
oscillation is minimal when the oscillation period is (5–10)
min. Furthermore, the glycolytic oscillation is found at work near
the phase boundary of limit cycles, suggesting that a moderate increase
of glucose injection rate leads to the loss of oscillatory dynamics,
which is reminiscent of the loss of pulsatile insulin release resulting
from elevated blood glucose level.