The MaxDiscovery™ Alkaline Phosphatase (AP) Enzymatic Assay Kit is a plate-based, colorimetric-endpoint assay for the determination of the alkaline phosphatase enzyme in serum. Alkaline phosphatase (AP) is a ubiquitously-expressed intracellular enzyme which catalyzes the hydrolysis of organic phosphoesters. AP is a clinically important protein marker in serum because its level changes in response to a number of health-related states. For example, changes in AP serum levels are often caused by liver and liver and bone diseases. Also, the presence of elevated levels of the enzyme in serum after administration of drugs and experimental therapeutic agents is associated with organ toxicity. Therefore, monitoring serum levels of AP enzyme has become a routine method to monitor drug toxicity. MaxDiscovery™ Alkaline Phosphatase Enzymatic Assay Kit uses an enzymatic assay to determine the amount of alkaline phosphatase in rodent serum and other liquid samples. The kit enables biomedical researchers to determine alkaline phosphatase levels in liquid samples such as serum. The MaxDiscovery™ Alkaline Phosphatase Enzymatic Assay Kit contains sufficient materials to test 42 samples in duplicate. The assay utilizes a simple colorimetric (visible) enzymatic assay to specifically detect AP in fluids. The MaxDiscovery™ Alkaline Phosphatase Enzymatic Assay Kit provides accurate, proven results even in complex liquid mixtures. The kit is designed to be used with a microplate reader. The kit contains a thymolphthalein standard to construct a linear calibration curve and verify assay performance.