A two-step purification of mouse liver glyoxalase I and evidence of its dimeric constitution

Glyoxalase I (S-lactoyl-glutathione methylglyoxal-lyase (isomerizing), EC 4.4.1.5) was purified from Swiss mouse liver to homogeneity by a rapid, two-step procedure involving hydrophobic and affinity chromatography. Homogeneity was established by multiple electrophoretic determinations and by sedimentation equilibrium centrifugation. The purified enzyme exhibited a specific activity of 944 I.U./mg protein an has a molecular weight of 43 000. The enzyme was shown to be a dimer by sodium dodecyl sulfate disc gel electrophoresis and is apparently composed of identical subunits of molecular weights approximating 21 500.