Irvine Chemistry Lab
X-Lyz™ Conjugation Density Assay

Determination of Conjugation-to-Protein Ratio

  1. X-Lyz™ Reagent A
  2. X-Lyz™ Reagent B
  3. User Instruction

Please see the MSDS for safely handling.
Contact us for questions, testing services.

  • 15min quick assay
  • Wide linear range
  • Compatible with reducing agents
  • Suitable for microplates and cuvettes
Product Description

Conjugation with amino groups in proteins is commonly achieved by
NHS ester or EDC-like agents.  However, these reagents are quickly
hydrolyzed in an aqueous media.  For instance, the NHS ester may
decompose to its parent inactive acid completely in less than 10min;
its half time may drop by 10-30 fold as the pH is raised from 7.0 to
8.5.   The final conjugation ratios could be very inconsistent especially
in dilute solutions.  It is a requirement to have a simple and reliable
analytical tool to determine the outcome out of a particular reaction and
to ensure its reproducibility.

The X-Lyz™ Conjugation Density Assay Kit is designed to provide a
quick quantitative analysis for conjugation ratios. It measures the
amine contents in the protein before and after the reaction. The
amount of conjugated amines and ratio may then be obtained. In
practice, there is no need to know the actual protein concentration in
the sample. The assay involves a reaction with primary amines to form
a chromophore. It exhibits a strong UV absorbance at 350nm linearly
proportional to concentrations over a wide range of 25-6,000nmol/mL.  
The rapid color development is complete after 15min incubation. The
assay is easy to operate compared to other methods, such as
trinitrobenzenesulfonic acid (TNBS), known as a dangerous explosive
substance.  The X-Lyz™ reagent is compatible with commonly used
materials in the laboratory, such as reducing agents, detergents,
alcohols, carbohydrates, and inorganic salts. The method is suitable
for assays in microplates and test tube (cuvettes).  More details may
be found in the instruction below.

Figure 1: Amine concentrations of BSA and BGG versus
absorbance at 350nm. The assay was conducted in 2mL
cuvettes with a spectrophotometer, WR/Sample 1/1, sample size
Catalog #
User Instructions
# of Assays
# of Assays
Test Tube
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