Catalysts with a gentle touch

In over three billion years since life first emerged on our planet, evolution has generated millions of enzymes to catalyse thousands of different reactions. In contrast, in the past 100 years or so, chemists have discovered and invented a much smaller number of catalysts for use in industry. Most synthetic catalysts are less selective than enzymes; they often operate best at high temperatures or in otherwise harsh conditions, and they may generate toxic by-products. It is not surprising that, by the mid-20th century, chemists were turning to the natural world for alternative catalysts, but as most reactions needed by the chemical industry are not found in nature, no enzymes have specifically evolved to carry them out. Enzyme engineering techniques are now widespread throughout the chemical and biotechnology industries, including in multinationals like Merck and Johnson Matthey. Enzyme active sites are strongly reminiscent of the structure of synthetic metal–organic frameworks, or MOFs, which are considered to have important industrial applications