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Trusted by Leading Research and Pharma Institutions

Carboxyl-Reactive Biotinylation Services

Target carboxylic acid groups on Asp/Glu residues and C-termini using high-efficiency EDC chemistry. Preserve critical active sites and maintain native conformation for your most sensitive biomolecules. Our carboxyl-reactive platform offers superior results for acidic proteins and applications requiring specific orientation.

EDC Zero-Length Crosslinker
MES Buffer System
Activity Retention
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Trusted by leading research and pharmaceutical institutions

Harvard
Pfizer
MIT
Roche
Stanford
Novartis

Why Choose Us

Optimal pH 4.7-5.5 for EDC activation
PEG spacers prevent aggregation
HABA QC for degree of labeling
ESI-MS complete characterization

Hydrazide Chemistry

Stable hydrazide linkages at pH 4.7-5.5

Activity Preserved

Maintain native protein conformation

Amine-Free System

MES buffer for optimal reactivity

Activity Retention
95%+
Overview Technology Specifications Workflow Applications FAQ
Service Overview

Why Choose Carboxyl-Reactive Biotinylation

When traditional amine-reactive NHS-esters risk compromising protein function by targeting lysines in receptor-binding domains or enzymatic pockets, carboxyl-reactive biotinylation emerges as the strategic alternative.

Asp/Glu/C-Terminus Targeting

Our advanced platform targets carboxylic acid groups found at Asp/Glu residues distributed across protein surfaces, enabling optimal orientation for surface immobilization on streptavidin-coated sensors or magnetic beads.

  • Surface-exposed Asp/Glu residues
  • C-terminal carboxyl groups
  • Alternative for lysine-rich proteins

Active Site Preservation

Unlike amine-reactive methods that may modify lysines in active sites, our carboxyl-reactive approach preserves critical enzymatic and binding functions while achieving uniform labeling density.

  • Preserves enzymatic activity
  • Maintains receptor binding
  • Native conformation retention

MES Buffer System

Optimal pH 4.7-5.5 for EDC activation without interference from primary amines or carboxylates.

Zero-Length Crosslinking

EDC chemistry forms direct amide bonds without introducing additional spacer molecules.

Flexible Spacer Options

PEG spacers prevent aggregation and enhance solubility for sensitive applications.

Need Expert Guidance for Your Biotinylation Project

Our technical team will help you choose between hydrazide and alkyamine strategies based on your specific application requirements.

Technology Platform

Our Carboxyl-Labeling Technology Platform

Proprietary EDC chemistry paired with carefully selected biotin-hydrazide or biotin-alkyamine reagents ensures homogeneous, highly-sensitive conjugates with preserved biological activity.

EDC/Hydrazide Coupling

Direct reaction of hydrazide-biotin with EDC-activated carboxylates forms stable hydrazide linkages particularly effective at pH 4.7-5.5.

Zero-Length Stable Bond

EDC/Alkyamine Coupling

Reaction of biotin-alkyamine with EDC-activated carboxylates creates longer spacer arms with enhanced flexibility for sterically hindered proteins.

Extended Spacer Flexible Arm

Amine-Free Conditions

MES buffer eliminates interference from primary amines, ensuring maximum coupling efficiency and minimal side reactions.

MES pH 4.7-5.5 No Tris/Glycine

Quality Control

HABA Degree of biotinylation quantification
MS ESI-MS mass verification
Activity Biological activity retention assay
COA Certificate of Analysis included

Reagent Options

Hydrazide Biotin-hydrazide for short spacers
Alkyamine Biotin-alkyamine for extended spacers
PEG PEGylated versions for solubility
Custom Tailored spacer length available
Specifications

Flexible Options for Diverse Needs

Comprehensive specifications to meet your research requirements.

Parameter Hydrazide Biotin Alkyamine Biotin PEGylated Version
Reaction Chemistry EDC activation with hydrazide EDC activation with alkyamine EDC activation with PEG-spacer
Optimal pH 4.7-5.5 4.7-5.5 4.7-5.5
Reaction Temperature Room temperature or 4C Room temperature or 4C Room temperature or 4C
Reaction Time 2-4 hours 2-4 hours 2-6 hours
Buffer Compatibility MES only, no amines MES only, no amines MES only, no amines
Target Residues Asp, Glu, C-termini Asp, Glu, C-termini Asp, Glu, C-termini
Workflow

Streamlined Process from Design to Delivery

Our proven 5-step workflow ensures quality and efficiency at every stage.

1

Consultation

Protein assessment and strategy development

2

Optimization

Buffer and reaction condition optimization

3

Conjugation

EDC-mediated biotinylation reaction

4

QC

HABA assay, ESI-MS verification

5

Delivery

Purification and quality documentation

Applications

Diverse Applications Across Biotechnology

Our carboxyl-reactive biotinylation supports research and development in multiple fields.

Biosensor Surface Immobilization

Optimize protein orientation on streptavidin-coated sensor surfaces for maximum binding capacity and signal-to-noise ratio in SPR, QCM, and electrochemical biosensors.

  • Surface plasmon resonance (SPR) sensors
  • Quartz crystal microbalance (QCM) chips
  • Electrochemical sensor platforms
  • Optical waveguide lightmode spectroscopy
Controlled
Surface orientation for optimal sensitivity

Immunoassay Development

Preserve antigen binding sites while achieving uniform labeling for ELISA, Western blot, and immunoprecipitation applications. The carboxyl-reactive approach ensures reproducible orientation.

  • Sandwich ELISA formats
  • Western blot detection
  • Immunoprecipitation (IP)
  • Multiplex assay platforms
95%+
Activity retention guaranteed

Proteomics and Interaction Studies

Enable site-specific biotinylation for mass spectrometry workflows, protein interaction studies, and proximity labeling applications. HABA QC provides precise degree of labeling quantification.

  • Affinity purification mass spectrometry
  • Protein-protein interaction studies
  • Proximity-dependent biotinylation
  • Biotinylation site mapping
ESI-MS
Complete characterization included
Testimonials

What Our Clients Say

Trusted by researchers worldwide for quality and reliability.

The carboxyl-reactive biotinylation preserved our enzyme activity completely. We achieved excellent SPR results with uniform protein orientation on the sensor surface. Highly recommended for any biosensor project requiring active proteins.

S
Senior Scientist
Biotechnology Company

We needed to biotinylate an Asp/Glu-rich acidic phosphatase without losing enzymatic activity. The carboxyl-reactive approach delivered exactly what we needed. The technical support team was extremely helpful in optimizing the conditions.

M
Research Director
Academic Research Institution

Excellent service for our therapeutic antibody labeling project. The MES buffer system and PEG spacer options were exactly what we needed for our sensitive proteins. The HABA QC data gave us confidence in our degree of labeling.

J
Lead Researcher
Pharmaceutical Company
Scientific Literature

Scientific Foundation

Our platform is backed by peer-reviewed research.

89 Citations

Streptavidin Coverage on Biotinylated Surfaces

Hamming PHE, Huskens J. ACS Applied Materials and Interfaces. 2021.

Quantitative prediction method for streptavidin coverage on biotinylated surfaces using quartz crystal microbalance and localized surface plasmon resonance.

View DOI
45 Citations

Thiol-Cleavable Biotin for Chemical and Enzymatic Biotinylation and Its Application to Mitochondrial TurboID Proteomics

Li H, Frankenfield AM, Houston R, Sekine S, Hao L. Journal of the American Society for Mass Spectrometry. 2021.

Exploration of thiol-cleavable biotin as an alternative approach for eluting biotinylated proteins from streptavidin-coated beads.

View DOI
38 Citations

Detectability of Biotin Tags by LC-MS/MS

Nierves L, Lange PF. Journal of Proteome Research. 2021.

Comparison of commercial biotin labels for LC-MS/MS detection, including effects on peptide hydrophobicity and charge.

View DOI
12 Citations

AviTrap: A Novel Solution to Achieve Complete Biotinylation

Lu C, Bevers J, Tyagi T, To H, Lin M, Ti S, et al. PLOS ONE. 2024.

Development of monoclonal antibody for specifically recognizing non-biotinylated AviTag to enrich fully biotinylated proteins.

View DOI
28 Citations

Tuning Gold-Based Surface Functionalization for Streptavidin Detection: A Combined Simulative and Experimental Study

Dutta S, Gagliardi M, Bellucci L, Agostini M, Corni S, Cecchini M, Brancolini G. Frontiers in Molecular Biosciences. 2022.

Multiscale simulations and experiments investigating streptavidin binding mechanisms on biotinylated gold surfaces for biosensor development.

View DOI
FAQ

Frequently Asked Questions

Find answers to common questions about our service.

What is the difference between carboxyl-reactive and amine-reactive biotinylation?
Carboxyl-reactive biotinylation targets Asp/Glu residues and C-termini using EDC chemistry at pH 4.7-5.5, while amine-reactive NHS-ester biotinylation targets lysine residues at pH 7-9. Carboxyl-reactive methods are ideal when lysines are present in active sites or when a different spatial distribution of biotin is needed.
Why is MES buffer used instead of other buffers?
MES buffer (pH 4.7-5.5) provides the optimal pH for EDC activation of carboxyl groups while containing no primary amines or carboxylates that would interfere with the coupling reaction. Common buffers like Tris, glycine, and phosphate-citrate contain interfering groups.
What is the difference between biotin-hydrazide and biotin-alkyamine?
Biotin-hydrazide forms a shorter spacer with a hydrazide functional group that reacts with EDC-activated carboxyls. Biotin-alkyamine provides a longer carbon chain spacer with enhanced flexibility, which can be advantageous for sterically hindered proteins or when additional distance from the protein surface is desired.
How do you determine the degree of biotinylation?
We use the HABA (4-hydroxyazobenzene-2-carboxylic acid) assay, which measures biotin-streptavidin binding competition to quantify the number of biotin molecules per protein. ESI-MS analysis is also performed to verify the mass shift corresponding to biotin incorporation.
Can PEG spacers help with protein aggregation?
Yes, PEG (polyethylene glycol) spacers significantly reduce protein aggregation and improve solubility. The hydrophilic PEG chain provides steric hindrance that prevents hydrophobic interactions between labeled proteins, making PEGylated biotin reagents ideal for sensitive or aggregation-prone proteins.
What is the typical turnaround time?
Standard projects are completed within 10-15 business days, including consultation, optimization, conjugation, and quality control. Rush services are available for urgent projects. The initial consultation phase may extend the timeline for first-time projects requiring extensive optimization.
What proteins are best suited for carboxyl-reactive biotinylation?
Carboxyl-reactive biotinylation is particularly suitable for proteins with lysines in active sites, enzymes with critical lysine residues, acidic proteins rich in Asp/Glu residues, and applications requiring specific protein orientation on sensor surfaces. Our team can assess your protein and recommend the optimal strategy.
Do you offer custom spacer lengths?
Yes, we offer a range of standard spacer options and can accommodate custom spacer length requests for specialized applications. Please discuss your specific requirements with our technical team during the consultation phase.

Ready to Start Your Project?

Get a customized quote for your Carboxyl-Reactive Biotinylation Services project. Our experts will respond within 24 hours.

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24h response
Expert consultation

Recommended Services

· Amine-Reactive Biotinylation Services
· Sulfhydryl-Reactive Biotinylation Services

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