Rhamnogalacturonan exolyase

Rhamnogalacturonan exolyase (, YesX) is an enzyme with systematic name α- L -rhamnopyranosyl-(1→4)-α- D -galactopyranosyluronate exolyase. This enzyme catalyses the following chemical reaction


 * Exotype eliminative cleavage of α- L -rhamnopyranosyl-(1→4)-α- D -galactopyranosyluronic acid bonds of rhamnogalacturonan I oligosaccharides containing α- L -rhamnopyranose at the reducing end and 4-deoxy-4,5-unsaturated D -galactopyranosyluronic acid at the non-reducing end. The products are the disaccharide 2-O-(4-deoxy-β- L -threo-hex-4-enopyranuronosyl)-α- L rhamnopyranose and the shortened rhamnogalacturonan oligosaccharide containing one 4-deoxy-4,5-unsaturated D -galactopyranosyluronic acid at the non-reducing end.

The enzyme is part of the degradation system for rhamnogalacturonan I in Bacillus subtilis strain 168.