摘要：Abstract Enzymes are used in various sectors of industry. Invariably, industries procure these enzymes from the vendors. Such commercial preparations are seldom of high purity. Hence reporting catalytic data obtained with such enzyme preparations poses some special challenges in addition to the usual ones associated with enzymology. This chapter discusses some of these challenges. The purity of an enzyme is the first such issue in view of the impure nature of the commercial preparations of the enzymes. One should be cautious in relying upon the kinetic data obtained with such preparations. Estimation of the protein content can be challenging as often the nature of the interfering substances, if any, is unknown. Measurement of the total number of activity units requires careful attention to many possible pitfalls. It is also necessary to be very clear about whether activity per unit mass relates to the weight of the solid or protein. Initial rates do not always give the correct picture about the usefulness of an enzyme for a particular reaction. Hence, the complete progress curve should be reported. Similarly, the operational stability under actual conditions of the application is more useful than stability in aqueous buffers. High activity of an enzyme preparation in low-water systems may be due to the reduction of mass transfer constraints rather than the high stability of the enzyme in such systems. Finally, the phenomena of moonlighting proteins and catalytic promiscuity have thrown fresh challenges as these questions the fundamental paradigm of one protein–one function.
关键词：Activity units;Protein estimation;Protein moonlighting;Enzyme promiscuity;Enzymes in organic solvents
