Recombinant SARS-CoV-2, S1 Subunit Protein (RBD)

Recombinant SARS-CoV-2, S1 Subunit Protein (RBD) with C-terminal His tag, derived from the transfected human HEK293 cells.


Product Specifications

100 ug, 500 ug, or 1000 ug
Supplied as a 0.2 um filtered solution in PBS (pH 7.4)
His-tag affinity purification by immobilized metal ion affinity chromatography (IMAC)
Concentration (lot specific):
Lot specific (see the label on the vial), determined by BCA protein assay
Purity determined by:
SDS-PAGE under reducing conditions and visualized by Coomassie blue staining
Recommended Applications:
Lateral flow, indirect ELISA, sandwich ELISA, glycosylation analysis, binding assay, antibody generation, hybridoma screening, western blotting, biotin/dye/bead conjugation, binder selection, crystallization, and vaccine development.
Sandwich ELISA: this protein functions as a standard in conjunction with 130-10815 (capture antibody) and 130-10814 (detection antibody).
Standard curve


Accession Number:
  • QHD43416
Expressed Region:
Protein Name & Synonyms:
Spike protein, S Protein, S1 Subunit, Host Cell Receptor Binding Domain (RBD)


Expression System:
Human Embryonic Kidney 293 (HEK293) Cells
Conjugation/Tag Notes:
C-terminal his-tag
Molecular Weight (kDa):
Recombinant protein product has a calculated molecular mass of 25 kDa. Due to the abundant glycosylation, it migrates as approximately 30 kDa protein bands in SDS-PAGE under DTT, beta-mercaptoethanol reducing conditions. See deglycosylation analysis image below.
Figure 1. Deglycosylation of purified recombinant proteins. Purified proteins were untreated (Lane 2) or treated with Protein Deglycosylation Kit under native (Lane 3) or reducing (Lane 4) conditions. Deglycosylation treatment resulted in a mobility shift of the protein to produce one major band at the expected size, thus indicating that the untreated recombinant protein (Lane 2) was glycosylated.
Lane 1: Protein standard ladder (kDa)
Lane 2: Untreated protein under reducing conditions
Lane 3: Treated protein with deglycosylation enzymes under native conditions
Lane 4: Treated protein with deglycosylation enzymes under reducing conditions.
Binding Function
Binding Function
Product binding ability was measured by ELISA. The immobilized recombinant human ACE2 protein (Catalog #230-30165, coated at 0.5 ug/ml, 100 ul/well) was incubated with the serial diluted SARS CoV-2 S1 RBD wild type protein (Catalog #230-30162). The bound protein was detected by mouse anti-S1 RBD monoclonal antibody using ELISA. The calculated EC50 is 32.77 ng/ml.

Stability & Storage

Ice packs
Upon arrival, the protein may be stored for 2 weeks at 4 °C. For long term storage, it is recommended to store at -20 °C or -80 °C in appropriate aliquots. Avoid repeated freeze-thaw cycles.

Related Coronavirus Proteins

Spike Protein, S1 Subunit, Host Cell RBD
Spike Protein, S2 Subunit
Nucleocapsid Protein
S1 Subunit Protein (RBD) with C-terminal Fc tag
S1 Subunit Protein (RBD) with C-terminal His-tag
S1 Subunit Protein with C-terminal His-tag
S2 Subunit Protein with C-terminal His-tag
Nucleocapsid Protein with C-terminal His-tag

Custom Labeling Request

We can custom label this protein with biotin or fluorescent dyes (choose from violet, blue, green or red). Request now.
  1. Beltrán-Pavez C, et al. Insights into neutralizing antibody responses in individuals exposed to SARS-CoV-2 in Chile. Science Advances (2021).
    Sample type:
  2. Borchers C, et al. Evaluation of SARS-CoV-2 spike S1 protein response on PI3K-mediated IL-8 release. Med Sci (Basel) 18;9(2):30 (2021).
    Sample type:
  3. Keshavarz B, et al. Quantitative measurement of IgG to severe acute respiratory syndrome coronavirus-2 proteins using immunoCAP. Int Arch Allergy Immunol. 182(5):417-424 (2021).
    Sample type:
  4. Miller CJ, et al. FN3-based monobodies selective for the receptor binding domain of the SARS-CoV-2 spike protein. N Biotechnol (2021).
    Sample type:
  5. Luetkens T, Metcalf R, Planelles V, Zheng Y, Larragoite ET, Spivak ES, Spivak AM, Steinbach M, Blaylock RC, Avila SV, Hankey KG, Martins TB, Slev PR, Mannuel HD, Sajadi M, Rapoport AP, Atanackovic D. Successful transfer of anti-SARS-CoV-2 immunity using convalescent plasma in an MM patient with hypogammaglobulinemia and COVID-19. Blood Adv. 2020 Oct 13;4(19):4864-4868. doi: 10.1182/bloodadvances.2020002595. PMID: 33031540; PMCID: PMC7556131.
    Species: Human
    Sample type: Plasma
  6. Huang W-C., Zhou S., He X., et al. SARS-CoV-2 RBD Neutralizing Antibody Induction is Enhanced by Particulate Vaccination. Adv. Mater. 2020, 2005637
    Species: Human
    Sample type: Conditioned Media
  7. Antonopoulos A, et al. Site-specific characterisation of SARS-CoV-2 spike glyocprotein receptor binding domain. Glycobiology, cwaa085 (2020).
    Sample type:
We emploied this protein for site-specific glycosylation analysis. It works great.

University of California, Davis
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This product is furnished for LABORATORY RESEARCH USE ONLY.
Not for diagnostic or therapeutic use.