phosphatase is created which not only has a 36-fold increase in enzyme activity, but also retains thermal stability. Typical uses in the lab for alkaline phosphatases include removing phosphate monoesters to prevent self-ligation, which is undesirable during plasmid DNA cloning. Common alkaline phosphatases used in research include: Shrimp alkaline phosphatase (SAP), from a species of Arctic shrimp (Pandalus borealis). This phosphatase is easily inactivated by heat, a useful feature in some applications. Calf-intestinal alkaline phosphatase (CIP) Placental alkaline phosphatase (PLAP) and its C terminally truncated version that lacks the last 24 amino acids (constituting the domain that targets for GPI membrane anchoring) – the secreted alkaline phosphatase (SEAP). It presents certain characteristics like heat stability, substrate specificity, and resistance to chemical inactivation. Human-intestinal alkaline phosphatase. The human body has multiple types of alkaline phosphatase present, which are determined by a minimum of three gene loci. Each one of these three loci controls a different kind of alkaline phosphatase isozyme. However, the development of this enzyme can be strictly regulated by other factors such as thermostability, electrophoresis, inhibition, or immunology. Human-intestinal alkaline phosphatase shows around 80% homology with the bovine intestinal enzyme which holds true their shared evolutionary origins. That same bovine enzyme has more than 70% homology with human placental enzyme. However, the human intestinal enzyme and the placental enzyme only share 20% homology despite their structural similarities. Alkaline phosphatase has become a useful tool in molecular biology laboratories, since DNA normally possesses phosphate groups on the 5' end. Removing these phosphates prevents the DNA from ligating (the 5' end attaching to the 3' end), thereby keeping DNA molecules linear until the next step of the process for which they are being prepared; also, removal of the phosphate groups allows radiolabeling (replacement by radioactive phosphate groups) in order to measure the presence of the labeled DNA through further steps in the process or experiment. For these purposes, the alkaline phosphatase from shrimp is the most useful, as it is the easiest to inactivate once it has done its job. Another important use of alkaline phosphatase is as a label for enzyme immunoassays. Undifferentiated pluripotent stem cells have elevated levels of alkaline phosphatase on their cell membrane, therefore alkaline phosphatase staining is used to detect these cells and to test pluripotency (i.e., embryonic stem cells or embryonal carcinoma cells). There is a positive correlation between serum bone alkaline phosphatase levels and