Physiological and biochemical characterization of glyoxalase I, a general marker for cell proliferation, from a soybean cell suspension.

Using a strictly auxin-dependent soybean (Glycine max (L.) Merr.) cell suspension, we studied the correlation of auxin-dependent cell proliferation and the activity of glyoxalase I (S-lactoylglutathione-lyase EC 4.4.1.5), and enzyme generally associated with cell proliferation in animal, microbial and, as reported recently, also plant systems. We found the activity of glyoxalase I to be modulated during the proliferation cycle, with a maximal activity between day 2 and day 4 of culture growth. After starving the culture of auxins for three subsequent periods, both the enzyme activity and cell-growth could be re-initiated with auxin. Enzyme activity reached its maximum 1 d before cell number was at a maximum. The enzyme was purified to homogeneity and characterized.