Description_x000D_ General description_x000D_ Diamine Oxidase (DAO) is an important regulator of polyamine levels in human physiology. DAO metabolizes the oxidative conversion of biogenic polyamines such as putrescine and cadaverine into aldehydes. Biogenic amines are known regulators of important biological pathways such as cell growth and signal transduction, placing DAO in an important regulatory position in maintaining cell viability. Putrescine itself is also an activator of c-jun and c-fos expression, further linking this diamine with potential roles in cancer development. DAO is notably involved in regulating growth and differentiation of intestinal mucosa, bone marrow, and other rapidly proliferating tissue. In addition to its role in tissue growth, DAO activity is important in metabolism. Loss of diamine oxidase activity can lead to histamine intolerance and histamine poisoning._x000D_ Suitability_x000D_ Suitable for the measurement of DAO activity in various tissues and cell extracts as well as the characterization of DAO activity of purified recombinant enzyme._x000D_ Principle_x000D_ The Diamine Oxidase Activity Assay Kit provides a straightforward method to determine DAO activity of tissue lysates as well as recombinant enzymes, with a detection limit of less than 1 pmole/minute of activity. In the assay, DAO converts the provided substrate, yielding an intermediate and H2O2. H2O2 is then utilized by the DAO Enzyme Mix to generate fluorescence (Ex/Em = 535/587 nm) from the DAO Probe.