Osmoregulated periplasmic glucans are a family of oligosaccharides found in the periplasm of Gram negative bacteria. Mutants devoid of OPGs show strong reduction or absence of virulence on their hosts and display pleiotropic phenotype. Glucose is the sole constituent sugar and OPG level increases as the osmolarity of the medium decreases. OPG synthesis is regulated both at the transcriptional and at the enzymatic level. Data presented in this article indicate that in addition, OPG synthesis requires constant synthesis of protein indicating rapid turnover of one of the two proteins catalyzing glucose backbone of OPGs.