lactate metabolic process(GO:0006089) methylglyoxal metabolic process(GO:0009438) methylglyoxal catabolic process to D-lactate via S-lactoyl-glutathione(GO:0019243) ketone catabolic process(GO:0042182) methylglyoxal catabolic process(GO:0051596) methylglyoxal catabolic process to lactate(GO:0061727)