natural sources could be considered for commercialization. Even some natural enzymes had properties not directly suitable for a particular industrial application. Now it is possible to produce any enzyme in industrially useful form by cloning the gene and expressing it in a suitable production organism. The properties of the enzyme, such as stability, selectivity, and catalytic efficiency, are controlled by its three-dimensional structure. This structure is in turn determined by the sequence of amino acids in the enzyme, which can now be altered by changing the gene that codes for the enzyme. The researcher can fit the desired application by changing the amino acid sequence in the enzyme. This has been done for several enzymes in commercial use and will lead to the increased use of enzymes as catalysts for industrial processes.
Another area of rapidly emerging opportunity is the formation of catalytically active antibodies targeted for specific reactions. Various approaches are available. These include the raising of antibodies to structures resembling those of the transition states of the reactions for which a catalyst is desired. Recent studies have demonstrated rate accelerations for a number of antibody-catalyzed reactions of up to 106 times the uncatalyzed rate. A development in the design of catalytic antibodies involves the introduction of catalytic activity into antibodies via either molecular biological or chemical means. These strategies allow for the a priori evolution of catalytic activity in an antibody combining site and also allow incremental increases in the rates of catalytic antibodies generated by other means. Examples of such approaches include introduction of catalytic groups via hapten-antibody complementarity, chemical modification, generation of cofactor binding sites, and site-directed mutagenesis. These systems offer catalysts for reactions beyond those available from enzymes.
Within the United States, the design and synthesis of new catalytic materials have been pursued largely in industry but have received much less attention in government and university laboratories. This is not the case in Japan and the European Community, where considerable research on catalyst synthesis is evident, and in fact targeted, in many academic research institutions. The absence of a strong effort toward the synthesis and evaluation of all types of novel materials is a weakness in the catalysis program in the United States. Not only does this sharply limit the techniques that can be brought to bear on problems in this area, but it also curbs the opportunities for discovery.
As illustrated by the examples presented above, many exciting research opportunities are available for the design and synthesis of all types of new catalytic materials, and strong support should be given to this important area.