A general enzyme-driven rule of metabolic scaling with body mass and
evolution in organisms
Abstract
The origin and dynamics of the metabolic scaling is a fundamental
problem in ecology and related sciences. The famous power law was
queried by the notable variations of the power exponent and the
non-log-linear curvature of metabolic scaling. Here, we proposed a novel
enzyme-driven model of metabolic scaling based on the hypothesis that
the key enzyme constrained the relative rate of both metabolism and
growth based on the basic biochemical evidences. The predictions were
tested by the broad range of compiled database from prokaryotes to
higher animals. The results showed that: (1) both metabolism (Q) and
body mass (m) were increased with the rate-limiting enzyme activity
exponentially, (2) both natural logarithmic metabolism (lnQ) and body
mass (lnm) were limiting resource dependent, and (3) lnQ was lnm
dependent, that is the non-log-linear scaling, when Q and m had the
different half-saturation constant of substrate response (KQ ≠ Km) and
log-linear scaling when KQ = Km, which showed how and why the variation
of scaling dynamics and the exponent. The results mean that the dynamics
of metabolic scaling may be mainly originated from the enzymatic
dynamics and the lnQ and lnm dependent model may be more general than
the power law of metabolic scaling