L-Citrulline-p-nitroanilide hydrobromide is a substrate for enzymes such as beta-galactosidase, beta-glucuronidase, and alkaline phosphatase. It is used in biochemical assays for the detection of microorganisms and in medical diagnostics. This compound has been shown to be useful in fluorescence microscopy and bioluminescence. It also has applications in food testing, environmental testing, and high purity research.