Recombinant Human ST3GAL4 His-tag Protein, CF

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Recombinant Human ST3GAL4 His-tag Protein, CF Summary

Learn more about Fluorescent Glycan Labeling and Detection

Product Specifications

>80%, by SDS-PAGE visualized with Silver Staining and quantitative densitometry by Coomassie® Blue Staining.
Endotoxin Level
<1.0 EU per 1 μg of the protein by the LAL method.
Measured by its ability to transfer Neu5Ac from CMP-Neu5Ac to alpha -lactose. The specific activity is >100 pmol/min/μg, as measured under the described conditions.
Mouse myeloma cell line, NS0-derived human ST3GAL4 protein
Glu41-Phe333, with a C-terminal 6-His tag
Accession #
Predicted Molecular Mass
34 kDa
39-41 kDa, under 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 and NaCl.
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, -20 to -70 °C as supplied.
  • 3 months, -20 to -70 °C under sterile conditions after opening.

Assay Procedure

  • Assay Buffer: 50 mM Tris, 5 mM MnCl2, pH 7.0
  • Sialyltransferase Activity Kit (Catalog # EA002)
  • Recombinant Human ST3GAL4 (rhST3GAL4) (Catalog # 10496-GT)
  • CMP-Sialic Acid (Sigma, Catalog # C8271), 10 mM stock in deionized water
  • alpha -Lactose (Sigma, Catalog # L2643), 0.3 M stock in deionized water
  • 96-well Clear Plate (Catalog # DY990)
  • Plate Reader (Model: SpectraMax Plus by Molecular Devices) or equivalent
  1. Dilute 1 mM Phosphate Standard provided by the Sialyltransferase Activity Kit by adding 40 µL of the 1 mM Phosphate Standard to 360 µL of Assay Buffer for a 100 µM stock. This is the first point of the standard curve.
  2. Complete the standard curve by performing six one-half serial dilutions of the 100 µM Phosphate stock using Assay Buffer. The standard curve has a range of 0.078 to 5 nmoles per well.
  3. Prepare a reaction mixture containing 0.2 mM CMP-Sialic Acid, 36 mM alpha -Lactose and 2 µg/mL Coupling Phosphatase 2 (supplied in kit) in Assay Buffer.
  4. Dilute rhST3GAL4 to 8 µg/mL in Assay Buffer. *Note: Perform single dilution step if possible to achieve concentration and avoid any acute mechanical stresses such as vortexing.
  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 8 µg/mL rhST3GAL4 into empty wells of the same plate as the curve. Include a Control containing 25 µL of Assay Buffer.
  7. Add 25 µL of reaction mixture to the wells, excluding the standard curve.
  8. Seal plate and incubate at room temperature for 30 minutes.
  9. Add 30 µL of the Malachite Green Reagent A (supplied in kit) to all wells. Mix briefly.
  10. Add 100 µL of deionized water to all wells.
  11. Add 30 µL of the Malachite Green Reagent B (supplied in kit) 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:
  • rhST3GAL4: 0.2 µg
  • Coupling Phosphatase 2: 0.05 µg
  • CMP-Sialic Acid: 0.1 mM
  • alpha -Lactose: 18 mM
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: ST3GAL4

Sialyltransferases add sialic acid to glycoproteins or glycosphingolipids and play important roles in many biological processes including immune recognition, pathogen infection, and cell adhesion (1). ST3GAL4 is an alpha 2,3-sialyltransferase and forms alpha 2-3 linked sialic acid on the Gal residue of the terminal Gal beta 1-4GlcNAc and Gal beta 1-3GalNAc structures found on glycoproteins and glycolipids (2, 3). ST3GAL4 is involved in the synthesis of sialyl Lewis x (sLex) glycan epitope that may serve as ligands for E- and P-selectins on activated endothelial cells in inflammatory responses (4). Down-regulation of ST3GAL4 mRNA may be one of the factors associated with the malignant progression of human renal cell carcinoma (5). ST3GAL4 is expressed as a type II membrane protein localized in the trans-Golgi apparatus but may also be proteolytically processed to form a soluble form. The activity of the recombinant human ST3GAL4 was determined using a phosphatase‑coupled glycosyltransferase assay (6).

  1. Varki, A. (1999) Glycobiology 2:25.
  2. Kitagawa, H. and Paulson, J.C. (1994) J Biol Chem. 269:1394.
  3. Basu, S.S. et al. (1996) Biochemistry 35:5166.
  4. Higai, K. et al. (2006) FEBS Letters 580:1873.
  5. Saito, S. et al. (2002) Oncology reports  9:1251.
  6. Wu, Z.L. et al. (2011) Glycobiology 21:727.
Long Name
ST3 beta-Galactoside alpha-2,3-Sialyltransferase 4
Entrez Gene IDs
6484 (Human); 20443 (Mouse); 363040 (Rat)
Alternate Names
Alpha 2,3-sialyltransferase IV; Alpha 2,3-ST 4; Beta-galactoside alpha-2,3-sialyltransferase 4; CGS23; CGS23FLJ46764; EC 2.4.99; EC 2.4.99.-; EC; FLJ11867; gal-beta-1,4-GalNAc-alpha-2,3-sialyltransferase; Gal-NAc 6S; gal-NAc6S; NANTA3; NANTA3alpha-3-N-acetylneuraminyltransferase; SAT3; SAT-3; sialyltransferase 4C (beta-galactosidase alpha-2,3-sialytransferase); sialyltransferase 4C (beta-galactoside alpha-2,3-sialytransferase); Sialyltransferase 4C; SIAT4; SIAT4C; SIAT4-C; SIAT4CCMP-N-acetylneuraminate-beta-galactosamide-alpha-2,3-sialyltransferase 4; ST3 beta-galactoside alpha-2,3-sialyltransferase 4; ST3Gal IV; ST3GAL4; ST3GalA.2; ST3GalIV; ST-4; STZSIAT4

Citation for Recombinant Human ST3GAL4 His-tag 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.

1 Citation: Showing 1 - 1

  1. Fluorescent glycan fingerprinting of SARS2 spike proteins
    Authors: ZL Wu, JM Ertelt
    Scientific Reports, 2021-10-14;11(1):20428.
    Species: Human
    Sample Types: Recombinant Protein
    Applications: Bioassay


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