Donald J. Tipper

Enzymes that degrade bacterial cell walls

Publisher Summary This chapter focuses on the mechanism of enzymes that degrade bacterial cell walls. The cell walls of all bacteria are composed of two or more polymers. They are ubiquituous in the bacterial world, are responsible for the shape and strength of the walls, and allow the cells to live in environmental conditions which are hypotonic with respect to their high intracellular osmotic pressure. These polymers are a glycopeptide built up of polyacetylhexosamine and peptide chains, and the action of all bacteriolytic enzymes. The basic structure of the peptide subunits is probably similar to that found in uridine diphosphate (UDP)-acetylmuramyl-peptide cell wall precursors. Some or all of the peptide chains linked to adjacent polysaccharide backbones are in turn linked to each other, resulting in a network of at least two dimensions. The digestion of different bacterial walls by various bacteriolytic enzymes gives rise to fragments of highly diverse nature and molecular complexity. A lyric intrapeptide hydrolase induces the appearance of new terminal amino and carboxyl groups. The enzymes that degrade the glycopeptide of bacterial cell walls and of which the specificity is at least partially known, are tabulated in the chapter.