May catalyze the conversion of methylglyoxal (MG) to D-lactate in a single glutathione (GSH)-independent step. May play a role in detoxifying endogenously produced glyoxals. Involved in protection against reactive oxygen species (ROS). H2O + methylglyoxal = (R)-lactate + H(+) Belongs to the peptidase C56 family. HSP31-like subfamily. Lacks the conserved active site residues critical for glyoxalase activity. Its enzyme activity is therefore unsure.