Name: Biotinylated SARS-CoV-2 Spike S1 Domain
Brand: Molecular Depot
SKU: B2010508
Price: 695.00 USD
Availability: InStock

<h2>What are protein conjugates in this category?</h2>
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Protein Conjugates are recombinant target proteins, such as receptors or other binding partners, labeled with biotin through site-specific Avi-tag enzymatic biotinylation or fused to an antibody Fc region, giving the protein a defined chemical handle for capture on a streptavidin-coated surface or purification via Protein A/G resin. This differs from Immunoglobulin Conjugates, where the conjugated molecule is an antibody itself; here, the protein being studied is the one carrying the conjugate, supporting applications like screening for binding partners or building a defined capture surface around your specific target.
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<h2 dir="ltr">What you will find:</h2>
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Enzyme-Linked Reporting Probes: High-purity target proteins conjugated to horseradish peroxidase or alkaline phosphatase for powerful chemiluminescent and colorimetric detection.
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Biotinylated Capture Complexes: Specialized macromolecular configurations engineered to exploit ultra-high-affinity streptavidin systems for sensitive target isolation and signal enhancement.
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Secondary Detection Systems: Calibrated protein links prepared to bind primary target molecules reliably, ensuring clear baseline identification in multi-tier immunoassay setups.
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<h2>How to choose protein conjugates</h2>
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Choose Avi-tag biotinylation for uniform, site-specific protein orientation
Avi-tag biotinylation enzymatically attaches a single biotin molecule to one lysine residue within a short, defined peptide sequence, producing a homogeneous product with consistent orientation when bound to a streptavidin-coated surface, unlike chemical biotinylation, which can label multiple, less predictable sites.
Choose an Fc-fusion conjugate for Protein A/G-based purification and capture
An Fc-fusion conjugate, with the Fc region of an antibody (commonly human IgG1) fused to your target protein, can be purified and captured using Protein A or Protein G resin, leveraging the same chemistry used elsewhere in antibody purification workflows.
Confirm whether bioactivity is preserved in the conjugated form
A biotinylated or Fc-fusion conjugate should report bioactivity similar to its unlabeled counterpart, and checking conjugate-specific binding or activity data, rather than assuming it matches the unlabeled parent protein, helps confirm the conjugation hasn't disrupted the protein's natural function.
Decide whether you need a combined multi-tag construct
Some protein conjugates combine an Fc-fusion region, an Avi-tag for biotinylation, and an additional purification tag like polyhistidine in a single construct, supporting multiple downstream uses, such as purification, capture, and detection, from one product.
Confirm degree of biotinylation if precise stoichiometry matters
Biotinylation is typically confirmed to a specific minimum percentage, such as 90% or higher, and checking this confirmed degree of labeling matters for applications sensitive to the exact biotin-to-protein ratio, such as some quantitative binding assays.
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<h2>Specifications context</h2>
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Avi-tag biotinylated proteins are typically confirmed to be at least 90% biotinylated, with the biotin attached to a single lysine residue within the Avi-tag peptide sequence, providing enhanced control over protein orientation in binding assays compared with chemical biotinylation approaches. As of 2026, biotinylated and Fc-fusion protein conjugates remain widely used tools for screening protein-protein interactions and antibody or small molecule libraries, leveraging the predictable, well-characterized attachment chemistry these conjugate formats provide.
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Protein Conjugates

Molecular Depot

Key Specifications

Biotinylated SARS-CoV-2 Spike S1 Domain

Biotinylated SARS-CoV-2 Spike S1 Domain by Molecular Depot is a highly pure biotinylated recombinant S1 domain of the SARS-CoV-2 spike protein from the original wild type lineage, expressed in insect cells. It has a molecular weight of about 76 kDa. It is used with streptavidin surfaces in serological assays and antibody screening. Each unit contains 25 µg. MBP supplies Molecular Depot protein reagents to research labs in the United States, Canada and worldwide.