M. Cascante et al., ENZYME-ENZYME INTERACTIONS AND METABOLITE CHANNELING - ALTERNATIVE MECHANISMS AND THEIR EVOLUTIONARY SIGNIFICANCE, Biochemical journal, 298, 1994, pp. 313-320
Metabolite channelling may result from different kinetic mechanisms in
which enzyme-enzyme interactions occur, so that intermediates are not
released into the bulk solution and cannot be used by enzymes outside
the channel. From an evolutionary point of view, the emergence of suc
h mechanisms may provide new functional possibilities for the system,
which would result in a selective advantage. Hence, it would be useful
to evaluate the objective advantages provided by the various options
by considering different criteria for functional effectiveness. Follow
ing this strategy, the goal of this paper is to compare a model for a
free-diffusion two-enzyme system with two different models with inclus
ion of enzyme-enzyme interactions. In addition, models with simultaneo
us free and interacting branches are also analysed, and their advantag
es or disadvantages are presented. Basic guidelines are suggested that
help in predicting the occurrence of specific mechanisms in different
circumstances, and provide theoretical evidence in support of the hyp
othesis that no single solution simultaneously optimizes all the possi
ble desired properties of the system.