Shrimp Alkaline Phosphatase
Shrimp Alkaline Phosphatase (SAP) – still the golden standard and the first heat-labile alkaline phosphatase on the market. It is a multipurpose alkaline phosphatase that can be fully inactivated by a short heat treatment.
100% heat-inactivated at 65°C
Works in restriction enzyme buffers
Used in PCR clean-up
Removes 5’-phosphates from DNA, RNA, dNTPs and dephosphorylates proteins
Also available in Glycerol-free formulation
Unit definition: One Unit will convert 1 µmol of p-nitrophenyl phosphate per minute to nitrophenol and phosphate at 37ºC and pH 10.4 in 0.1 M glycine buffer, 1 mM each of ZnCl2 and MgCl2 and 6 mM 4-nitrophenyl phosphate.
This Unit definition makes 1 Unit of SAP equivalent to 5 to 40 Units of Antarctic Phosphatase (New England Biolabs), 1.3 Units APex phosphatase or 35 Units NTPhos phosphatase (Epicentre Biotechnologies). SAP is therefore the most processive alternative.
- Specific activity: >2 000 Units/mg.
- Purity: DNase activities not detected.
- Concentration: Minimum 10 000 Units/ml, available up to 30 000 Units/ml.
- Batch sizes: 25 – 35 million Units / batch.
Stable at -20ºC in storage buffer (25 mM Tris-HCl pH 7.6, 5 mM MgCl2, glycerol 50%). At room temperature, >95% activity remains after 90 days.
Still, the enzyme is completely inactivated after 5 minutes at 65°C. At 75°C, SAP is completely inactivated after only 1 minute. In a standard thermocycler, the process of heating from 37 to 95 and back to 37°C is sufficient to completely inactivate SAP.
Recombinant SAP is covered by the following patents: US 7,323,325, EP 1,326,890, JP 4,191,479, AU 9,398,701 and related applications in other countries either granted or pending.