Presence of glyoxalase II in mitochondria from spinach leaves: comparison with the enzyme from cytosol.

Glyoxalase II has been purified from cytosol and mitochondria of spinach leaves. Electrophoresis and isoelectric focussing have resolved cytosolic and mitochondrial glyoxalase II in multiple forms: pl 5.3, 5.8 and 6.2 (cytosol) and pl 4.8 (mitochondria). The enzyme of both localizations is a monomer showing a relative molecular mass of about 26 kDa. The values of kinetic constants using several glutathione thiolesters as substrates, are similar for the enzymes from cytosol and mitochondria. These results extend also to plant the presence in mitochondria of peculiar forms of glyoxalase II, likewise recently demonstrated in mammalians.