The results presented in this thesis indicate that the future for
ab initio computational simulations in biological disciplines is
extremely promising. Several avenues of investigation of the
cytochrome P450 enzyme system are immediately suggested. Further steps
in the catalytic cycle, including the reduction of the system by its
redox partners and the binding of 
at the active site, may be
explored. This would offer information about intermediary states in
the catalytic cycle which are not directly accessible to conventional
experimental techniques. Such simulations could also permit the
calculation of reaction rates which are thought to be limited by the
rate of the second reduction of the active site complex (See Chapter
). A scheme for predicting the action of a cytochrome P450
enzyme on a given molecule would be of enormous benefit to the
pharmaceutical industry. Such a tool would offer savings in time and
money in the development of potential drug compounds which must be
tested for their activity with cytochrome P450 enzymes. Any approach
to predictive simulations would obviously require the consideration of
the specificity of human cytochrome P450s. This in turn requires
accurate models of the geometry of the active sites of these enzymes
which is are subjects of current investigations (see for example
[132] and [133]). Ab initio simulations may
also have a rôle to play in these investigations. Comparison of
experimental observations with calculated reaction characteristics for
a ligand in different orientations within the active site would allow
models of the active site structure to be tested. Using current
ab initio methods, the computational power is not available to
thoroughly explore questions of substrate specificity and orientation
within the active site. This is because a large number of possible
configurations must be tested to determine the optimum orientation of
a ligand or even if it will bind at all. However, these searches may
be efficiently performed using empirical approaches, although these
are less accurate than ab initio methods. It is possible that
the use of ab initio techniques in combination with empirical
fast-search methods might provide a suitable methodology to solve this
problem. A quick empirical search could suggest a few candidate ligand
orientations which would then be studied in detail using ab
initio simulations to compare their energies and model the reaction
mechanism.
Although the cytochrome P450 enzyme system offers an ideal target for ab initio modeling, there are many other enzymes and receptors which could be studied. With the increases in available computer power predicted over the next few years, the possible applications of ab initio computer simulations are almost boundless.