Enzymes are used for the diagnosis of diseases, that is, enzymatic diagnosis is a method for determining the content and changes of certain substances in the body by the catalytic action of the enzyme, or for diagnosing the disease by the change of the original enzyme activity in the body.
Besides protein engineering, chemical approaches including chemical modification and immobilization are employed in designing biocatalysts with desirable bio-properties for industrial applications. Enzyme immobilization, first commercialized in the 1960s, has been well developed to facilitate the reusability and recovery of enzymes. High stabilization of a biocatalyst, such as pH and thermal stability, can often be achieved through immobilization, and enhanced activities are demonstrated in an increasing number of recent reports.