AJP - Regulatory, Integrative and Comparative Physiology, Vol 237, Issue 5 350-R354, Copyright © 1979 by American Physiological Society
Flux of labeled compounds in biochemical oscillations
L. K. Kaczmarek
If a labeled compound (e.g., a radioisotopically or chemically labeled
metabolite) is introduced into any biochemical reaction system, the label
will be removed by catabolic reactions and replaced by unlabeled compound
through anagolic reactions. It is shown that the removal of labeled
compounds is particularly efficient if the rates of the catabolic steps are
able to oscillate. This is demonstrated by comparing reaction schemes that
maintain the same mean fluxes and concentrations of metabolites and the
same overall chemical affinity but which differe in that the rate of
catabolism is either constant or oscillates as a function of time. Simple
analyses are presented for both small and large oscillations of undefined
wave form and for sinusoidal oscillations. The enhanced removal of labeled
compounds from oscillating reaction systems is also documented by numerical
computation on a nonlinear model system. It is suggested that this ability
to remove labeled compounds may have provided a selective advantage for the
evolution of some biological oscillations.
