PE-Cy7 Conjugation Kit uses a simple and quick process for PE-Cy7 conjugation of antibodies. The kit provides all the reagents, purification columns needed to label up to 300 μg of antibody, as well as a detailed step-by-step protocol.
The PE-Cy7 Conjugation Kit is a SH-reactive labeling kit. The kit provides a Conjugation Reagent that reacts with primary amines (-NH₂) to introduce a SH group onto the antibody. Subsequently, Modified PE-Cy7 and sulfhydryl group on the antibody form a covalent bond during conjugation.
Fig. 1 PE-Cy7 Conjugation Kit (P1491953) Labeling Principle Schematic
Instruction for use
1. Antibody sulfhydryl modification
To add sulfhydryls to antibodies: Use Conjugation Reagent, which modify primary amines. Ensure antibodies have a free sulfhydryl to react with the maleimide group of SMCC Activated PE-Cy7.
1.1 Add Conjugation Buffer to dissolve the antibody to achieve a concentration of 3–5 mg/mL. A higher protein concentration is preferred. If less than 3 mg/mL, the antibody should be concentrated. If the IgG is not salt-free or if it is already in solution, the antibody must be transferred to the Conjugation Buffer via concentration exchange or dialysis.
1.2 Add 1 mL of purified water to the Conjugation Reagent and mix thoroughly. Note: The Conjugation Reagent solution must be prepared fresh before each use.
1.3 Add 2.8 µL of prepared Conjugation Reagent per 300 µg of antibody solution, briefly vortex to mix.
1.4 During the incubation prepare a desalting column.
1.4.1 Snap open the bottom of the column and insert the column into matching collection tube. Remove and discard the column cap and centrifuge for 2 min at 1000 x g. Discard eluate.
Note: When using a fixed-angle rotor, place a mark on the side of the column that faces away from the rotor center. For all subsequent centrifugation steps, place the column in the microcentrifuge with the mark facing away from the rotor center.
1.4.2 Apply 500 µL of Conjugation Buffer and centrifuge for 2 min at 1000 x g. Discard eluate.
1.4.3 Repeat step 1.4.2 for two additional times. Add Conjugation Buffer for the third wash but wait to centrifuge until immediately prior to proceeding to step.
1.4.4 After the third wash check there is no solution in the column, if required briefly centrifuge until no solution remains.
1.5 Insert prepared desalting column into a fresh Collection Tube and apply the entire sample from step 1.3 to the column.
1.6 Centrifuge at 1000 x g for 2 min. Retain the eluate, which is the activated antibody.
2. Conjugate with SMCC activated PE-Cy7
2.1 Prepare PE-Cy7 solution (5 mg/mL)—Add 200 μL of purified water to SMCC Activated PE-Cy7. Vortex gently until the solution is homogenous. Note: The Reconstituted SMCC Activated PE-Cy7 solution must be prepared fresh before each use.
2.2 Add the prepared antibody from step 1.6 to the prepared PE-Cy7 solution. Incubate the mixture at room temperature for 1 hour and keep away from light.
2.3 Block excess free thiols
2.3.1 Add 500 µL of DMSO into the Quencher Reagent. Note: The Quencher Reagent solution must be prepared fresh before each use.
2.3.2 Add 2.5 µL of prepared Quencher reagent into conjugation mixture from Step 2.2 and mix completely. Incubate at room temperature for 20 min and keep away from light.
2.4 Conjugation is complete. The reaction mixture should contain mostly the PE-Cy7-antibody conjugate, with small amounts of free PE-Cy7 and antibody. Unconjugated PE-Cy7 should not interfere with the assay.
Storage
1. Store the PE-Cy7-antibody conjugate at concentration > 0.5 mg/mL or add 1-10 mg/mL of BSA as a stabilizer.
2. Add preservative (e.g. 0.05% proclin 300).
3. Store the conjugate solution at 4°C in the dark for two months. DO NOT FREEZE.
4. If there is aggregation in the conjugate solution, centrifuge briefly for 30 sec and use the supernatant only.
Matters needing attention
1. Any primary amines in the IgG solution (e.g., Tris or glycine) will interfere with conjugation. If necessary, dialyze or desalt samples into an appropriate buffer, before use.
2. Before formal experimentation, allow all reagents to reach room temperature, as lower temperatures may impair conjugation efficiency.
3. Do not reuse the purification resin.
4. The reactive dyes should be protected from prolonged exposure to light.
5. During operation, always wear a lab coat, disposable gloves, and protective equipment.
6. All products are for research use only.
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