On the purification of L-ornithine decarboxylase from rat prostate and effects of thiol compounds on the enzyme.

The activity and stability of L-ornithine decarboxylase from rat ventral prostate is markedly increased by certain thiol compounds, notably dithiothreitol. The enzyme was purified about 300-fold. Many properties of the purified enzyme are described. In the absence of added thiol compounds, the purified ornithine decarboxylase apparently undergoes polymerization, as evidenced by its behavior on sucrose density gradients and in molecular sieving experiments. The larger forms of the enzyme appear to be catalytically inert, but can be reactivated by a number of sulfhydryl compounds, certain dithiols being superior to a number of monothiols in this respect.