3 Enzyme Tests in Bacterial Identification

Abstract

Identification of bacteria is based on results of characterization tests, which place the unknown organism in a defined group. The results of conventional tests applied to clinical isolates are usually not available in less than 2 days from receipt of specimen. A large number of enzyme classes have been studied in bacteria. Each class will be dealt with briefly, followed by the results of application of batteries of enzyme tests to characterization and identification of various bacterial taxa, and problems of handling quantitative enzyme data. This chapter discusses the study of iso-enzymes using electrophoretic techniques, in which enzymes performing the same catalytic activities are compared with regard to their electrophoretic mobility, as well as their substrate, cofactor and inhibitor specificities. Bacterial enzymes may be situated within the cell or secreted into the growth medium. Extracellular enzymes can be measured around bacterial growth on solid medium or in the supernatant of spent liquid medium. Within the prokaryotic cell three different localities have been defined—namely, the periplasm, the cytoplasmic membrane, and the cytoplasm.