Aldol® 495 phosphate is a chromo- and fluorigenic indicator forphosphatase activity. The colorless product is cleaved by acid andalkaline phosphatases secreted by bacteria in liquid media or on agarplates and yields an orange color. In addition, green fluorescencesignals are generated if a fluorescence enhancer or a suitable matrix ispresent. Aldol® 495 phosphate can also be used as detecting agent forphosphatase coupled antibodies in Western blot and enzyme immune assayapplications.Color and fluorescence formation is due to on an intramolecular aldolcondensation after enzymatic cleavage. The reaction proceeds equallywell in the presence and absence of oxygen, i.e., in aerobic andanaerobic cultures. Well detectable color/fluorescence of bacterialcolonies or liquid cultures is obtained within 16-48 h. In the presenceof purified phosphatase, color and fluorescence develops within minutesto few hours.