Endonuclease-Free Certification

Endonuclease-Free Certification
This test certifies any of a wide variety of products to be free of endonuclease contamination and ready for use in all DNA work.
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Service Description


  • Experienced - MO BIO has over 22 years of experience in providing Endonuclease-free certifications to many major medical device companies and suppliers of plastic consumables
  • Qualified - All MO BIO Services technicians receive extensive training and are qualified to test raw materials or end products for the presence of Endonucleases
  • Certified - MO BIO is ISO 9001:2008 certified for providing 3rd party independent laboratory testing services for the life science industry

Endonucleases are enzymes that cleave the phosphodiester bond within a polynucleotide chain. Restriction endonucleases and nickases are of particular concern to customers working with plasmids and cosmids. 

Testing your product lines for this common contaminant will add integrity to your products and will enable a wider range of customers to utilize your products for their experiments and applications.



Endonuclease Test Method

All testing apparatus are treated with Diethyl Pyrocarbonate (DEPC) water to inhibit possible endonuclease contamination of the experiment from outside sources. Test samples of the product are extracted and a portion of extract is incubated with a plasmid standard in a buffered solution with both sodium and magnesium ions. Negative and Positive controls are run with the test sample extract to verify the experimental procedure and technique. An unexposed plasmid standard is included to represent the negative control. The plasmid standard exposed to endonuclease is also included to represent the positive control.

All samples are incubated 17-18 hours at 37ºC and then heated to 65ºC for 5 minutes. After the heating period, the samples and controls are evaluated by agarose gel electrophoresis and a picture for the Certificate of Analysis and final report is taken. The test samples should show no cleaving/nicking in comparison to the negative control. The positive control should exhibit cleaving/nicking, indicating the effect of endonuclease/nickase activity on the plasmid standard pool that is used for all the samples.
Passing test criteria: The plasmid exposed to the test sample or extract must look exactly the same as the plasmid negative control that was exposed to sterile water. There must be no visible cleaving/nicking of the plasmid in the negative control. The positive control must show cleaving/nicking of the supercoiled plasmid for the test to be valid.

Test Sensitivity: 2 x 10-4 Units

Unit is defined as the amount of enzyme which will completely degrade 1µg of pBR322 DNA in 10 minutes at 37°C in DNase I Reaction Buffer

Contact Services

Contact Services

MO BIO Laboratories Inc. has over 22 years of experience in providing services that keep your products competitive and in demand. Our customers include many of the top plastics and medical device suppliers in the industry. As an ISO 9001:2008 certified company, MO BIO is committed to delivering the highest quality testing services to our customers. Our services specialists can also work with you to develop a custom testing schedule and/or custom tests that fit the specific needs of your products. MO BIO is located in Carlsbad, CA, USA.