Lysozyme catalysis: kinetics of the hydrolysis of cell wall oligosaccharides

The cleavage of cell wall tetrasaccharide, the beta(1 leads to 4)-linked dimer of the basic repeating disaccharide N-acetyl-D-glucosamine-beta(1 leads to 4)-N-acetyl-D-muramic acid, by lysozyme has been studied at various concentrations of lysozyme and over long time ranges. A theoretical analysis of the kinetic results indicates that direct hydrolysis of the tetrasaccharide by binding in subsities CDEF of the active site of lysozyme is significant at long times relative to the transglycosylation pathway. The binding constant for tetrasaccharide in CDEF is shown to be 10(3) times larger than that determined on the basis of an analysis of kinetic data over a more restricted range of times and concentrations.