Catalytically Inactive Endoglycosidases as Microbial Diagnostic Reagents: Chitinases and Lysozymes as Fungal and Bacterial Capture/Label Agents

A. Roger Laine, Louisiana State University
W. C.Jennifer Lo, Louisiana State University
C. R.Betty Zhu, Louisiana State University


Catalytically disabled forms of enzymes have been used as carbohydrate recognition and detection systems. Such mutated enzymes have been developed for detection of bacterial infections and fungal infections. Such enzymes have low turnover number rendering them "catalytically inactive" in the time frame of the observation event. Therefore endoglycosidases employed as fungal or bacterial detection systems in a "catalytically inactive mode," utilize only their binding specificity. The use of cell wall polymer degradative enzymes as targeted diagnostic agents has several advantages such as high specificity for the target polymer, high avidity, much more economical than antibodies, and no nonspecific binding in human tissues. Catalytically inactive enzymes constitute a new class of capture/label reagents useful in the several types of assays, including slide-based stains, fluorescence, ELISA (enzyme-linked immunosorbent assay), dipsticks, latex agglutination assays, skin disclosure stains (skin, nail fungi, onchyomycosis), flow cytometry (for bacteria or yeast forms of fungi), and surface plasmon resonance. © 2007 Elsevier B.V. All rights reserved.