Trusted by Leading Research and Pharma Institutions

Protein Biotinylation Service

Site-specific enzymatic biotinylation using BirA biotin ligase technology for homogeneous, oriented protein labeling with 100% specificity. Preserve protein function while achieving uniform 1:1 labeling ratio.

100% Site-Specific

Uniform 1:1 Ratio

>95% Efficiency

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Trusted by leading research and pharmaceutical institutions

Harvard

Pfizer

MIT

Roche

Stanford

Novartis

Why Choose Us

Enzymatic precision with BirA ligase

ESI-MS verification on every sample

Preserved protein functionality

Expert consultation included

Site-Specific Labeling

AviTag sequence ensures biotin at exactly one site

Quality Guaranteed

Gel-shift assay and mass spec verification

Flexible Options

In vitro and in vivo labeling available

Labeling Efficiency

>95%

Service Overview

Site-Specific Protein Biotinylation Solutions

Our platform combines the specificity of BirA enzymatic biotinylation with comprehensive quality verification for homogeneous protein labeling.

Enzymatic Precision

BirA biotin ligase exclusively targets the AviTag sequence, ensuring modification at exactly one predetermined lysine residue. No off-target modifications, no heterogeneity.

15-amino acid AviTag recognition
Single modification site guaranteed
Native protein structure preserved

Uniform Labeling Ratio

Every protein molecule receives exactly one biotin tag, providing consistent batch-to-batch results critical for quantitative assays and structural studies.

Homogeneous 1:1 labeling ratio
Consistent batch-to-batch quality
Ideal for quantitative applications

Oriented Immobilization

Proteins orient consistently on streptavidin surfaces with active sites facing outward for optimal binding accessibility.

Complete QC Package

Gel-shift assay with streptavidin and high-resolution ESI-MS verification included with every project.

Flexible Positioning

AviTag can be placed at N-terminus, C-terminus, or internal flexible loops based on your protein structure.

Technology Platform

Advanced Biotinylation Technologies

Proven enzymatic platform ensuring high-quality output for every project.

BirA Enzymatic System

The BirA biotin ligase from E. coli catalyzes covalent attachment of biotin to the AviTag sequence (GLNDIFEAQKIEWHE) with exceptional specificity.

15-aa AviTag Single Site

AviTag Engineering

Structural modeling determines optimal tag positioning at N-terminus, C-terminus, or internal loops to ensure accessibility and function preservation.

N/C/Internal TEV Cleavage

Flexible Methods

Both in vitro enzymatic labeling of purified proteins and in vivo co-expression systems available to match your workflow requirements.

In Vitro In Vivo

Quality Verification

Gel-Shift Streptavidin binding assay

ESI-MS High-resolution mass spectrometry

HABA Biotin quantification assay

COA Certificate of Analysis included

Host Expression Systems

E. coli AVB101 or co-expression strains

Yeast Pichia pastoris systems

Mammalian HEK293 and CHO cells

Cell-Free PURE system options

Parameter	Specification
Labeling Method	Enzymatic (BirA biotin ligase)
Target Sequence	15-amino acid AviTag (GLNDIFEAQKIEWHE)
Modification Site	Single lysine residue within AviTag
Labeling Efficiency	>95% (verified by gel-shift assay)
Labeling Ratio	Uniform 1:1 (biotin:protein)
Protein Scale	0.1 mg to 100 mg per project
Tag Positioning	N-terminus, C-terminus, or internal loops
Host Systems	E. coli, Yeast, Mammalian cells (in vivo option)
Purity Requirement	>90% (SDS-PAGE verified)
Delivery Format	Lyophilized or solution in desired buffer

Parameter

Specification

Labeling Method

Enzymatic (BirA biotin ligase)

Target Sequence

15-amino acid AviTag (GLNDIFEAQKIEWHE)

Modification Site

Single lysine residue within AviTag

Labeling Efficiency

>95% (verified by gel-shift assay)

Labeling Ratio

Uniform 1:1 (biotin:protein)

Protein Scale

0.1 mg to 100 mg per project

Tag Positioning

N-terminus, C-terminus, or internal loops

Host Systems

E. coli, Yeast, Mammalian cells (in vivo option)

Purity Requirement

>90% (SDS-PAGE verified)

Delivery Format

Lyophilized or solution in desired buffer

Applications

Diverse Applications Across Biotechnology

Our biotinylation service supports research and development in multiple fields.

Research Applications

Site-specific biotinylation enables precise protein immobilization for various research applications requiring homogeneous samples.

Surface Plasmon Resonance (SPR) binding kinetics
Protein microarrays with consistent orientation
Single-molecule studies (TIRF, AFM)
Immunoprecipitation with streptavidin beads

100%

Homogeneous labeling

Diagnostic Development

Consistent biotin-streptavidin binding enables reproducible production of diagnostic reagents and assay development.

ELISA sandwich immunoassay development
Lateral flow assay optimization
Multiplex immunoassay reagents
Point-of-care device development

10-15 M

Biotin-Streptavidin Kd

Therapeutic Research

Site-specific labeling supports targeted therapeutic development and companion diagnostic applications.

ADC site-specific conjugation chemistry
CAR-T cell engineering with biotinylated antibodies
Targeted drug delivery systems
Biomarker validation studies

244 Da

Minimal tag footprint

Testimonials

What Our Clients Say

Trusted by researchers worldwide for quality and reliability.

"The uniformity of the biotinylated proteins was remarkable. Every batch showed identical behavior in our SPR experiments, which was impossible with chemical labeling."

Senior Scientist

Biotechnology Company

"We needed homogeneous samples for cryo-EM studies. The site-specific biotinylation delivered exactly what we needed. The 1:1 ratio simplified specimen preparation."

Principal Investigator

Academic Research Institution

"For our multiplex assay development, having consistent reagents is critical. The enzymatic biotinylation service has become essential to our diagnostic workflow."

Research Director

Diagnostics Company

Scientific Literature

Scientific Foundation

Our platform is backed by peer-reviewed research.

892 Citations

Site-specific labeling of cell surface proteins with biophysical probes using biotin ligase

Chen I, Howarth M, Lin W, Ting AY | Nature Methods. 2005.

BirA ligase enables sequence-specific biotinylation of the AviTag for protein labeling and purification applications.

View DOI

182 Citations

Imaging proteins in live mammalian cells with biotin ligase and monovalent streptavidin

Howarth M, Ting AY | Nature Protocols. 2008.

Protocol for labeling cell surface proteins using BirA and monovalent streptavidin in live mammalian cells.

View DOI

1247 Citations

Efficient proximity labeling in living cells and organisms with TurboID

Branon TC, Bosch JA, Sanchez AD, et al. | Nature Biotechnology. 2018.

TurboID biotin ligase enables rapid proximity labeling in living cells with improved efficiency compared to BioID.

View DOI

215 Citations

Site-Specific Biotinylation of Purified Proteins Using BirA

Fairhead M, Howarth M | Methods in Molecular Biology. 2015.

Detailed protocols for site-specific biotinylation of purified AviTagged proteins using BirA enzyme.

View DOI

389 Citations

Proximity labeling in mammalian cells with TurboID and split-TurboID

Cho KF, Branon TC, Udeshi ND, et al. | Nature Protocols. 2020.

Comprehensive protocols for TurboID and split-TurboID proximity labeling in mammalian cells.

View DOI

FAQ

Frequently Asked Questions

Find answers to common questions about our service.

What is the difference between enzymatic and chemical biotinylation?

Chemical biotinylation (NHS-biotin) targets general functional groups like primary amines, resulting in random modification at multiple sites. This creates heterogeneous products where each molecule may have zero, one, or multiple biotin tags. Enzymatic biotinylation using BirA specifically recognizes the AviTag sequence and modifies only one predetermined lysine residue, producing homogeneous 1:1 labeled products.

Can BirA biotinylate proteins without an AviTag?

No. BirA has exceptional substrate specificity and only recognizes the AviTag peptide sequence (GLNDIFEAQKIEWHE). For proteins without this specific sequence, chemical biotinylation methods must be used. We can provide AviTag insertion services via genetic engineering if needed.

How do you verify that biotinylation is complete?

We use multiple verification methods. The streptavidin gel-shift assay shows complete biotinylation when all protein shifts to a higher molecular weight band. High-resolution ESI-MS mass spectrometry provides definitive confirmation with exact mass increase. We also offer optional functional assays to verify biological activity preservation.

Where should the AviTag be positioned on my protein?

The optimal position depends on your protein structure and application. The AviTag can be placed at the N-terminus, C-terminus, or within internal flexible loops. We recommend positioning the tag at a surface-accessible location distal from active sites to ensure full protein function. Our team provides recommendations based on structural modeling.

What sample requirements must be met for the service?

Proteins should be delivered at >90% purity (SDS-PAGE verified), concentrated at 1-5 mg/mL in a suitable buffer (PBS or similar, free of primary amines like Tris or glycine). Buffer exchange can be performed as an additional service if needed. Endotoxin levels should be below 10 EU/mg for mammalian cell applications.

Is the AviTag removable after biotinylation?

Yes. We can include a protease cleavage site (TEV or Thrombin) between your protein and the AviTag. After biotinylation and streptavidin capture, the protease can be added to cleave between the protein and the biotin tag, releasing the native protein while the biotin remains attached to the AviTag fragment on the streptavidin surface.

What is the stability of biotinylated proteins?

The covalent biotin-lysine bond is extremely stable under normal storage conditions. Biotinylated proteins can be stored at -80C for extended periods with multiple freeze-thaw cycles without significant degradation. We provide detailed storage recommendations with each delivery, and lyophilized formats offer maximum long-term stability.

What factors affect BirA biotinylation efficiency?

Multiple factors influence biotinylation efficiency: AviTag accessibility (must be surface-exposed), protein concentration, buffer composition (avoid primary amines and nucleotides), temperature and incubation time, and enzyme quality. Our standard protocol achieves >95% conversion for accessible AviTags within 1 hour at 30C.

How does BirA compare to HaloTag or SNAP-tag?

BirA/AviTag uses a 15-amino acid peptide tag (244 Da) with an extremely stable covalent bond. HaloTag uses a 33 kDa protein tag with haloalkane ligands, and SNAP-tag uses a 20 kDa protein tag with benzylguanine derivatives. Both HaloTag and SNAP-tag have larger footprints that may affect protein function, but offer more ligand flexibility.

Can AviTag proteins be used in living cells?

Yes, through several approaches: cell surface labeling with BirA in culture medium, in vivo co-expression in engineered E. coli strains (AVB101), ER-targeted BirA with KDEL signal for secretory pathway labeling, and TurboID proximity labeling for mapping protein interactions in live cells.

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24h response

Expert consultation

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Protein Biotinylation Service

Why Choose Us

Site-Specific Labeling

Quality Guaranteed

Flexible Options

Site-Specific Protein Biotinylation Solutions

Enzymatic Precision

Uniform Labeling Ratio

Oriented Immobilization

Complete QC Package

Flexible Positioning

Ready to Get Started?

Advanced Biotinylation Technologies

BirA Enzymatic System

AviTag Engineering

Flexible Methods

Quality Verification

Host Expression Systems

Service Specifications

Streamlined Process from Design to Delivery

Vector Design

Expression

Biotinylation

Purification

QC Verification

Delivery

Diverse Applications Across Biotechnology

Research Applications

Diagnostic Development

Therapeutic Research

What Our Clients Say

Scientific Foundation

Site-specific labeling of cell surface proteins with biophysical probes using biotin ligase

Imaging proteins in live mammalian cells with biotin ligase and monovalent streptavidin

Efficient proximity labeling in living cells and organisms with TurboID

Site-Specific Biotinylation of Purified Proteins Using BirA

Proximity labeling in mammalian cells with TurboID and split-TurboID

Frequently Asked Questions

Ready to Start Your Project?

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