Non-tumorigenic RWPE-1 and tumorigenic LNCaP prostate cell lysates display differential esterase activity and substrate specificity. A) Non-tumorigenic RWPE-1 and tumorigenic LNCaP cell lysates containing 120 μg of protein were separated on a native 10-20% polyacrylamide gel. The gels were stained with 800 μM α-naphthyl acetate, R-ANAA, or S-ANAA substrate and Fast Blue RR salt. Native molecular weight markers (left side) were used to estimate the relative migration of some esterase bands (right side). B) The 359 kDa n-PAGE LNCaP and RWPE-1 esterase bands stained with R-ANAA or S-ANAA were measured by densitometry. C) The 432 kDa n-PAGE LNCaP and RWPE-1 esterase bands were also measured by densitometry. Letters that are not the same are significantly different at P < 0.05.