Metabolic control theory: the geometry of the triangle.

The definitions of flux control coefficients and elasticity coefficients as given in the Metabolic Control Theory are introduced by geometrical considerations. It is shown that a method to determine the (non-normalized) control coefficients from the elasticity coefficients as well as the well-known summation and connectivity relationships can easily be derived in a geometric way. This method is explained in the light of a simple example, but it can be applied to any metabolic system. A software implementation (program "control") and possible applications to biotechnology are briefly presented.