Use of genetically prepared enzyme conjugates in enzyme immunoassay

Enzyme immunoassay, using enzymes crosslinked to either antibodies or antigens, has proved a valuable immunological tool for many years. Recently, gene fusion techniques have been used to prepare these enzyme conjugates. This method may be especially advantageous in cases where (1) the antigen is difficult and costly to obtain in large quantities or (2) when the activity of the marker enzyme or the affinity of the antibody or antigen is severely reduced or even destroyed by use of conventional linking methods such as chemical crosslinking. This article uses specific examples to illustrate the potential of gene fusion as a conjugation method.