One of the more impressive features of the living organism is the degree of control it is able to exercise over its chemistry.
A set of molecules in a given environment will react predictably according to the laws of chemistry. Quite often, as the synthetic organic chemist is ruefully aware, these laws allow more than one reaction to take place, and a multitude of products to be synthesized. The set of molecules that makes up the living organism is also governed by the laws of chemistry. The organism is able to, however, limit reactivity to a single product. In many cases this is a necessity; multiple reactions can often lead to unacceptable inefficiency or death.
Those involved in the synthesis of new, nonbiological materials with enhanced properties could benefit from this level of control. In the simple case, production of only the single desired product in high yields would be a great economic boon. On another level, this control could lead to the production of materials that are otherwise inaccessible. An obvious example is the modification of a polymer. Only with precise reaction control can all the monomers be modified in the same way.
Organisms achieve their required degree of control of chemical reactions through a mechanism of positive regulation. Under the conditions found in an organism, virtually no reaction will take place at a rate that is sufficient to sustain the life processes. Those that do occur take place only in the presence of a catalyst. To allow a reaction to occur, the organism simply synthesizes the catalyst that is specific for that reaction and does so only at the appropriate time and place and to the required extent. Should that reaction no longer be needed, the catalyst is destroyed or inactivated.