Product No. KLEN-RO


Filling-in reaction

Protocols of standard assays for partial and complete filling in can be found in LabFaqs.

Alternative protocol:

  1. In a 20-μL reaction, digest 0.1 to 4 μg DNA with a restriction endonuclease.
  2. Add 1 μL of 0.5 mM of each dNTP.
    Note: It is usually not necessary to inactivate the restriction endonuclease, to change buffers, or to repurify the DNA prior to adding Klenow enzyme. If you nevertheless experience problems, try to adjust the buffer conditions to the SURE/Cut incubation Buffer M (f.c. 10 mM Tris, 10 mM MgCl ¬2, 50 mM NaCl, 1 mM DTT, pH 7.5).
  3. Add 1 to 5 U of Klenow enzyme and incubate at 30 °C for 15 min.
  4. Stop the reaction by heating to +75 °C for 10 min or by adding 1 μL of 0.5 M EDTA.
    For restriction fragments produced by cleavage with different endonucleases, it is possible to repair one end selectively. This is done by cleaving with enzyme 1, repairing the ends, inactivating the Klenow fragment by heat (+75 °C for 10 min), and cleaving with enzyme 2.
    Note: Repair of 5′ extensions is carried out by Klenow 's polymerase activity, whereas repair of 3′ extensions is carried out by 3′->5′exonuclease activity. Due to the relative inactivity of exonuclease, this method is not desirable in cases where extensive repair of overhanging 3′ ends is required. In such situations, T4 DNA polymerase is recommended.

Social Media

LinkedIn icon
Twitter icon
Facebook Icon
Instagram Icon


Research. Development. Production.

We are a leading supplier to the global Life Science industry with solutions and services for research, biotechnology development and production, and pharmaceutical drug therapy development and production.

© 2021 Merck KGaA, Darmstadt, Germany and/or its affiliates. All Rights Reserved.

Reproduction of any materials from the site is strictly forbidden without permission.