Abstract
Glycogen is the predominant polysaccharide in living cells. Many microorganisms accumulate glycogen, which serves as an energy reserve to cope with harsh environmental conditions. Therefore, the functions of enzymes involved in glycogen synthesis and degradation must be deciphered to understand the survival mechanisms of microbes. However, these enzymes in bacteria, most of which are glycosyl transferases or glycosidases, have not been fully characterized. Although there are similarities, the processes of glycogen synthesis and degradation in bacteria are quite distinct from the same processes in eukaryotes. Considerable progress has been made in understanding the mode of glycogen metabolism in Escherichia coli. In addition to the common core pathway, the virulence factors of infecting enteropathogenic bacteria appear to be involved in glycogen degradation. This review will focus on the following: (i) enzymes involved in glycogen degradation in E. coli, (ii) comparisons of the glycogen enzymes within enterobacteria, and (iii) glycogen as a carbon source for infectious microbes.
