Recombinant Human SULT1A1 Protein, CF

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R&D Systems Recombinant Proteins and Enzymes
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Recombinant Human SULT1A1 Protein, CF Summary

Product Specifications

>95%, by SDS-PAGE under reducing conditions and visualized by silver stain
Endotoxin Level
<1.0 EU per 1 μg of the protein by the LAL method.
Measured by its ability to transfer sulfate from PAPS to 1-Napthol. The specific activity is >30 pmol/min/μg, as measured under the described conditions.
E. coli-derived human Cytosolic Sulfotransferase 1A1/SULT1A1 protein
Glu2-Leu295, with an N-terminal Met and 6-His tag
Accession #
N-terminal Sequence
Predicted Molecular Mass
35 kDa
34 kDa, reducing conditions

Product Datasheets

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Carrier Free

What does CF mean?

CF stands for Carrier Free (CF). We typically add Bovine Serum Albumin (BSA) as a carrier protein to our recombinant proteins. Adding a carrier protein enhances protein stability, increases shelf-life, and allows the recombinant protein to be stored at a more dilute concentration. The carrier free version does not contain BSA.

What formulation is right for me?

In general, we advise purchasing the recombinant protein with BSA for use in cell or tissue culture, or as an ELISA standard. In contrast, the carrier free protein is recommended for applications, in which the presence of BSA could interfere.


Formulation Supplied as a 0.2 μm filtered solution in Tris, NaCl and DTT.
Shipping The product is shipped with dry ice or equivalent. Upon receipt, store it immediately at the temperature recommended below.
Stability & Storage: Use a manual defrost freezer and avoid repeated freeze-thaw cycles.
  • 6 months from date of receipt, -70 °C as supplied.
  • 3 months, -70 °C under sterile conditions after opening.

Assay Procedure

  • Assay Buffer: 50 mM Tris, 15 mM MgCl2, pH 7.5 (1X Phosphatase Buffer 3)
  • Recombinant Human Cytosolic Sulfotransferase 1A1/SULT1A1 (rhSULT1A1) (Catalog # 5546-ST)
  • 3'-Phosphoadenosine-5'-phosphosulfate (PAPS) (Catalog # ES019)
  • 1-Naphthol (Sigma, Catalog # N1000), 10 mM in deionized water
  • Universal Sulfotransferase Activity Kit (Catalog # EA003)
  • 96-well Clear Plate (Costar, Catalog # 92592)
  • Plate Reader (Model: SpectraMax Plus by Molecular Devices) or equivalent
  1. Dilute 1 mM Phosphate Standard by combining 40 µL with 360 µL of Assay Buffer for a 100 µM stock. This is the first standard curve point.
  2. Prepare additional points by performing six one-half serial dilutions of the 100 µM Phosphate stock in Assay Buffer.  The standard curve has a range of 0.078 to 5 nmol per well.
  3. Prepare a reaction mixture containing 0.4 mM PAPS, 0.4 mM 1-Naphthol, and 0.02 mg/mL Coupling Phosphatase 3 in Assay Buffer.
  4. Dilute rhSULT1A1 to 20 µg/mL in Assay Buffer.
  5. Load 50 µL of each dilution of the standard curve into a plate. Include a curve blank containing 50 μL of Assay Buffer.
  6. Load 25 µL of the 20 µg/mL rhSULT1A1 into the plate. Include a Control containing 25 µL of Assay Buffer.
  7. Add 25 µL of reaction mixture to the wells, excluding the standard curve.
  8. Cover the plate with a plate sealer and incubate at 37 °C for 20 minutes.
  9. Add 30 µL of the Malachite Green Reagent A to all wells. Mix briefly.
  10. Add 100 µL of deionized water to all wells. Mix briefly.
  11. Add 30 µL of the Malachite Green Reagent B to all wells. Mix and incubate for 20 minutes at room temperature.
  12. Read plate at 620 nm (absorbance) in endpoint mode.
  13. Calculate specific activity:

     Specific Activity (pmol/min/µg) =

Phosphate released* (nmol) x (1000 pmol/nmol)
Incubation time (min) x amount of enzyme (µg)

     *Derived from the phosphate standard curve using linear or 4-parameter fitting and adjusted for Control.

Per Reaction:
  • rhSULT1A1: 0.5 µg
  • PAPS: 10,000 pmol (0.2 mM)
  • 1-Naphthol: 0.2 mM
  • Coupling Phosphatase 3: 0.5 µg
Reconstitution Calculator

Reconstitution Calculator

The reconstitution calculator allows you to quickly calculate the volume of a reagent to reconstitute your vial. Simply enter the mass of reagent and the target concentration and the calculator will determine the rest.


Background: Cytosolic Sulfotransferase 1A1/SULT1A1

Cytosolic sulfotransferases catalyze the sulfonation of many hormones, neurotransmitters, drugs, and xenobiotic compounds. They are distinct from Golgi resident sulfotransferases by the absence of transmembrane domains and are located in the cytoplasm (1, 2).  SULT1A1 is one of two phenol sulfotransferases with thermostable enzyme activity (2). The enzyme is more specific for sulfonation on catecholamines, phenolic drugs and neurotransmitters (3). Because of its ability to modify diverse promutagen and procarcinogen xenobiotics, it is implicated in a range of cancers (2). The crystal structure of the enzyme reveals that its active site is flexible and can accommodate diverse hydrophobic substrates with varying sizes, shapes and flexibility (4). The enzymatic activity of the recombinant human SULT1A1 is measured using a phosphatase-coupled assay (5).

  1. Falany, C. N. (1997) FASEB J. 11:206.
  2. Gamage, N. U. et al. (2006) Toxicol. Sci. 90:5.
  3. Wilborn, T.W. et al. (1993) Mol. Pharm. 43:70.
  4. Gamage, N. U. et al. (2003) J. Biol. Chem. 278:7655.
  5. Prather, B. et al. (2012) Anal. Biochem. 423:86.
Entrez Gene IDs
6817 (Human); 20887 (Mouse); 83783 (Rat)
Alternate Names
Aryl sulfotransferase 1; Cytosolic Sulfotransferase 1A1; EC 2.8.2; EC; HAST1/HAST2; Phenol sulfotransferase 1; Phenol-sulfating phenol sulfotransferase 1; P-PST 1; P-PST; PST; ST1A1; ST1A3; STP1 ; STP1MGC5163; STPMGC131921; sulfotransferase 1A1; sulfotransferase family, cytosolic, 1A, phenol-preferring, member 1; SULT1A1; Thermostable phenol sulfotransferase; thermostable phenol sulfotransferase1; ts-PST; TSPST1

Citations for Recombinant Human SULT1A1 Protein, CF

R&D Systems personnel manually curate a database that contains references using R&D Systems products. The data collected includes not only links to publications in PubMed, but also provides information about sample types, species, and experimental conditions.

3 Citations: Showing 1 - 3
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  1. LC-MS/MS quantification of sulfotransferases is better than conventional immunogenic methods in determining human liver SULT activities: implication in precision medicine
    Authors: C Xie, TM Yan, JM Chen, XY Li, J Zou, LJ Zhu, LL Lu, Y Wang, FY Zhou, ZQ Liu, M Hu
    Sci Rep, 2017;7(1):3858.
    Species: Human
    Sample Types: Protein
    Applications: Enzyme Assay
  2. Correlating chemical sensitivity and basal gene expression reveals mechanism of action.
    Authors: Rees M, Seashore-Ludlow B, Cheah J, Adams D, Price E, Gill S, Javaid S, Coletti M, Jones V, Bodycombe N, Soule C, Alexander B, Li A, Montgomery P, Kotz J, Hon C, Munoz B, Liefeld T, Dancik V, Haber D, Clish C, Bittker J, Palmer M, Wagner B, Clemons P, Shamji A, Schreiber S
    Nat Chem Biol, 2016;12(2):109-16.
    Species: Human
    Sample Types: Recombinant Protein
    Applications: Bioassay
  3. A versatile polyacrylamide gel electrophoresis based sulfotransferase assay.
    Authors: Wu ZL, Ethen CM, Larson S, Prather B, Jiang W
    BMC Biotechnol., 2010;10(0):11.
    Species: N/A
    Sample Types: Recombinant Protein
    Applications: Enzyme Assay


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