Unsaturated rhamnogalacturonyl hydrolase (, YteR, YesR) is an enzyme with systematic name 2-O-(4-deoxy-beta-L-threo-hex-4-enopyranuronosyl)-alpha-L-rhamnopyranose hydrolase. This enzyme catalyses the following chemical reaction
The enzyme is part of the degradation system for rhamnogalacturonan I in Bacillus subtilis strain 168.