Prostate cell lysate esterases form distinct bands when separated by 6% n-PAGE. A) RWPE-1, RWPE-2, LNCaP, DU 145, and PC3 cell lysates containing 120 μg of protein were separated by 6% n-PAGE followed by staining with either 800 μM α-naphthyl acetate, S-ANAA, or R-ANAA. Native molecular weight markers (left side) were used to calculate the relative migration of some esterase bands (right side). The B) 216 kDa and C) 198 kDa esterase bands visualized with S-ANAA were measured by densitometry. Letters that are not the same are significantly different at P < 0.05.