A unified theory of enzyme kinetics based upon the systematic analysis of the variations of k(cat), K(M), and k(cat)/K(M) and the relevant DeltaG(0 not equal) values-possible implications in chemotherapy and biotechnology.

To elucidate the kinetic properties of critical enzymatic situations that have previously escaped classification, we performed a systematic analysis of all the possible variations of the kinetic constants k(cat,) K(M,) and k(sp) = k(cat)/K(M,) encompassing all aspects of enzymology. The equation gives a total of thirteen theoretically possible cases, comprising the reference case plus 12 different sets of variations, which can be divided into six principal cases and six specular ones. The six relevant cases are examined individually in the context of each of the main chapters of enzymology, i.

Cancer chemoprevention: some complications and limitations.

Chemopreventive strategies are very attractive and have earned serious consideration as a potential means of controlling cancer incidence. However, the use of some anti-initiating entities (enzyme inducers or inhibitors) devised to reduce tumor initiation is controversial. Indeed, considering the double-edged-sword (activating or detoxifying) nature of drug metabolizing enzymes, any attempt to modulate such catalysts by dietary components (including drugs) may lead to cancer risk.