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 Pull Down Laboratory Service

KMD Bioscience has been dedicated to protein interaction research for many years. Protein interaction, an important direction in protein structure and function research, can reveal the interaction mode between molecules. KMD Bioscience, which can express recombinant proteins with GST, Myc-tag, Flag-tag, HA-tag and other tags in both prokaryotic and eukaryotic expression systems, has rich experience in recombinant protein expression. KMD Bioscience has sophisticated testing equipment and mature technology that are from Kyoto University, Japan. The co-immunoprecipitation and Pull Down technologies of KMD Bioscience come from Kyoto University's IPS laboratory in Japan, which ensures the accuracy of the experiments. KMD Bioscience, which insists on providing customers with high quality services, is able to provide one-stop technical services from recombinant protein preparation to pull down protein interactions detection to meet the needs of different customers.

Pull Down experiment, a technology to detect molecular interactions in vitro conditions, which is used to verify protein-protein interactions or to screen for target proteins. Pull down experiment is similar to co-immunoprecipitation technology, except that co-immunoprecipitation technology uses antibodies to cross-link magnetic beads or agarose, whereas this technology utilizes protein-protein and protein-other biomolecule interactions for the capture and study of the target molecules. The principle is that the tagged bait protein is captured by a solidified affinity ligand that specifically binds to the tag, generating a "secondary affinity support" that is used to purify other proteins that interact with the bait protein. Proteins interacting with the decoy protein can be detected by SDS-PAGE electrophoresis, or by further characterization of the purified and eluted protein complexes in combination with Western blot validation and LC-MS/MS.



KMD Bioscience has established and improved the GST fusion protein pull-down technology, streptomycin labeling pull-down technology, CO-IP technology, Chip-qPCR technology and other immunology-based detection technology service system, among which pull-down technology and streptomycin labeling pull-down technology are used for protein and nucleic acid (RNA/DNA) research, respectively.


Immunology Testing Services -GST Pull-down Experiment:


GST Pull-down, also called protein binding assay in vitro, is a method of verifying or finding interactions between proteins under in vitro conditions.



GST pull-down Experiment

Experimental principle

This technology utilizes the affinity of GST for glutathione (GSH)-coupled spherical beads, firstly, recombinant expression technology is used to express "bait" proteins tagged with GST (glutathione transferase), and then the bait proteins are incubated with cell lysates to capture target molecules able to bind to the bait proteins, and then agarose beads tagged with GSH are added, and the GSH catalyzes the linkage of the protein complexes onto agarose beads under the catalytic effect of GST, and then low-speed centrifugation is used to collect the above complexes for subsequent analyses, such as SDS-PAGE.


*Demonstrate predicted possible protein-protein interactions

*Search for unknown molecules that interact with known proteins


*Mostly use labeled (e.g., GST) antibodies for detection, which is widely applicable

*Simple to use and an effective method for direct detection of protein interactions


GST Pull-down Experiment Flow:



Immunology Testing Services - RNA/DNA Pull-down Experiments:


RNA/DNA pull-down is an important technique for studying RNA or DNA-protein interactions under in vitro conditions.


RNA/DNA pull-down experiment

Experimental principle

*The technique involves the in vitro transcription of a portion or the full length of the target RNA, labeled with a biotin-labeled RNA/DNA probe, and incubated with cytoplasmic protein extracts to form RNA/DNA-protein complexes. The above complexes are then separated from the cell lysate using streptavidin-labeled magnetic beads or agarose beads. Then elution, SDS-PAGE or silver staining are performed to verify the target molecules


*Verification of whether a protein interacts with the target RNA/DNA

*Purified proteins can be screened for binding to target RNA by mass spectrometry identification


*The technique is a common method for capturing RNA/DNA-protein complexes

*Enables validation or screening of interacting proteins for target RNA or DNA, such as validation or searching for transcription factors for specific genes


DNA/RNA Pull-down Experiment Flow:




Service Advantages:


--Skilled level of experimental operation, set up controls and replicates to exclude the influence of random interfering factors to ensure more reliable results

--Use of silver staining technology, higher sensitivity, SDS-PAGE electrophoresis results are more clear

--Experienced expert team for technical support to solve all kinds of pull down technical problems

--Proven protein platform for pull down products, fusion plasmids, SDS-PAGE results and Western Blot results

--Complete information analysis, with detailed lab reports and protein identification (mass spectrometry) available

--One-stop service from GST protein preparation to protein interaction detection, saving customers' valuable time


How to Order?

If you have any questions regarding our services or products, please feel free to contact us by E-mail: or Tel: +86-022-8216-4980;