[6] Immunological techniques for studying β-lactamases

This chapter presents the immunological techniques for studying β-lactamases. In principle, β-lactamases are no different from other enzymes with respect to their action with antisera, and many of the techniques are capable of much wider application than that has occurred in the past. The reason for describing them, however, is that they have a particular relevance to β-lactamases because many of the minor variants of this enzyme that are found in naturally occurring strains have been characterized by these immunological methods. Once antisera to a β-lactamase have been obtained, they can be used to study the enzymes in a number of ways. These include precipitation analyses both in solution and by gel diffusion. However, perhaps the most effective is by neutralization of enzyme activity because this can be studied with as little as 0.1 μg of enzyme in impure preparations.