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. 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.