Developed at ArcticZymes, first launched in 1993. Originates from the Arctic Shrimp (Pandalus borealis), from 2010 it has been produced as a recombinant version (rSAP). rSAP is better suited than native SAP (nSAP) for newer, more sensitive technologies.
Shrimp Alkaline Phosphatase (rSAP) has become one of today’s most-selling DNA modifying enzymes due to the added convenience through a complete heat inactivation. While most other alkaline phosphatases (from E. coli or Calf intestine) must be removed by extraction procedures, rSAP is completely inactivated after 15 minutes at 65°C. rSAP works well in common buffers without the requirement for other additions.
Main advantages with rSAP
- Very high specific activity
- 100% heat-inactivated at 65°C
- Removes 5’-phosphates from DNA, RNA, dNTPs and proteins
- May be added directly to restriction enzyme digests
- No vector purification necessary
- Requires no supplemental zinc or other additives for activity
- Works directly in many different buffers
- Easy treatment of unincorporated dNTPs in PCR products prior to DNA sequencing or SNP analysis
Properties
Specifications
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.
Stability
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.
