Amplite? Fluorimetric Sphingomyelinase Assay Kit *Red Fluorescence*. Five types of sphingomyelinase (SMase) have been identified based on their cation dependence and pH optima of action. They are lysosomal acid SMase, secreted zinc-dependent acid SMase, magnesium-dependent neutral SMase, magnesium-independent neutral SMase, and alkaline SMase. Among the five types, the lysosomal acidic SMase and the magnesium-dependent neutral SMase are considered major candidates for the production of ceramide in the cellular response to stress. Our Amplite? Fluorimetric Sphingomyelinase Assay Kit provides the most sensitive method for detecting neutral SMase activity or screening its inhibitors. The kit uses Amplite? Red as a fluorogenic probe to indirectly quantify the phosphocholine produced from the hydrolysis of sphingomyelin (SM) by sphingomyelinase (SMase). It can be used for measuring the SMase activity in blood, cell extracts or other solutions. The fluorescence intensity of Amplite? Red is proportional to the formation of phosphocholine, therefore to the SMase activity. Amplite? Red enables the assay readable either in fluorescence intensity or absorption mode. The kit is an optimized mix and read assay that can be used for real time monitoring of Smase activities. Our kit 13622 has been developed for monitoring acid SMase activity.