Product Class: Other

Topoisomerase I (E. coli)
neb31 recombinant 37 65 Heat

We are excited to announce that all reaction buffers are now BSA-free. NEB began switching our BSA-containing reaction buffers in April 2021 to buffers containing Recombinant Albumin (rAlbumin) for restriction enzymes and some DNA modifying enzymes. Find more details at www.neb.com/BSA-free.

Product Introduction

  • Catalyzes the relaxation of negatively-supercoiled DNA
  • Isolated from a recombinant source
  • Supplied with 10X Reaction Buffer
Catalog # Size Concentration
M0301S 100.0 units 5000 units/ml
M0301L 500.0 units 5000 units/ml

Product Information

Description

Topoisomerase I (E. coli) catalyzes the relaxation of negatively supercoiled DNA. Topoisomerase I has also been implicated in knotting and unknotting DNA (1) and in linking complementary rings of single-stranded DNA into double-stranded rings (2). The intact holoenzyme is a 97 kDa protein.

Product Source

An E. coli strain containing the cloned topA gene
This product is related to the following categories:

Reagents Supplied

Reagents Supplied

The following reagents are supplied with this product:

NEB # Component Name Component # Stored at (°C) Amount Concentration

Properties & Usage

Unit Definition

One unit is defined as the amount of enzyme that catalyzes the relaxation of  > 95% of 0.5 μg of pUC19 RF I (negatively supercoiled) DNA in 15 minutes at 37°C in a total reaction volume of 25 μl. DNA supercoiling is assessed by agarose gel electrophoresis in the absence of ethidium bromide.

Reaction Conditions

1X rCutSmart™ Buffer
Incubate at 37°C

1X rCutSmart™ Buffer
50 mM Potassium Acetate
20 mM Tris-acetate
10 mM Magnesium Acetate
100 µg/ml Recombinant Albumin
(pH 7.9 @ 25°C)

Activity in NEBuffers

NEBuffer™ 1: 25%
NEBuffer™ 2: 50%
NEBuffer™ 3: 0%
NEBuffer™ 4: 100%

Storage Buffer

10 mM Tris-HCl
35 mM (NH4)2SO4
50 mM KCl
1 mM DTT
0.1 mM EDTA
50% Glycerol
pH 7.5 @ 25°C

Heat Inactivation

65°C for 20 minutes

References

  1. Liu, L.F., Depew, R.E. and Wang, J.C. (1976). J. Mol. Biol.. 106, 439-452.
  2. Kirkegaard, K. and Wang, J.C. (1978). Nucl. Acids Res.. 5, 3811-3820.

Protocols, Manuals & Usage

Protocols

  1. Protocol for Topoisomerase I (E. coli) (M0301)

Usage & Guidelines

FAQs & Troubleshooting

FAQs

  1. Does Topoisomerase I relax all supercoiled DNA to the same degree or are the products an equilibrium of various conformations?
  2. If the DNA resulting from a Topoisomerase I reaction is run in an ethidium bromide gel and there seems to be no evidence of enzyme activity, what is the most probable explanation?
  3. What is the molecular weight of Topoisomerase I?
  4. Can Topoisomerase I relax both positively and negatively supercoiled DNA?
  5. Does E. coli Toposiomerase I have the same properties as the Vaccinia Topoisomerase I?
  6. Will Topoisomerase I produce single strand-breaks in a plasmid?
  7. Can you tell me more about the switch from BSA to Recombinant Albumin (rAlbumin) in NEBuffers?

Quality, Safety & Legal

Quality Assurance Statement

Quality Control tests are performed on each new lot of NEB product to meet the specifications designated for it. Specifications and individual lot data from the tests that are performed for this particular product can be found and downloaded on the Product Specification Sheet, Certificate of Analysis, data card or product manual. Further information regarding NEB product quality can be found here.

Specifications

The Specification sheet is a document that includes the storage temperature, shelf life and the specifications designated for the product. The following file naming structure is used to name these document files: [Product Number]_[Size]_[Version]

Certificate Of Analysis

The Certificate of Analysis (COA) is a signed document that includes the storage temperature, expiration date and quality controls for an individual lot. The following file naming structure is used to name these document files: [Product Number]_[Size]_[Version]_[Lot Number]

Safety DataSheets

The following is a list of Safety Data Sheet (SDS) that apply to this product to help you use it safely.

Legal and Disclaimers

Products and content are covered by one or more patents, trademarks and/or copyrights owned or controlled by New England Biolabs, Inc (NEB). The use of trademark symbols does not necessarily indicate that the name is trademarked in the country where it is being read; it indicates where the content was originally developed. The use of this product may require the buyer to obtain additional third-party intellectual property rights for certain applications. For more information, please email busdev@neb.com.

This product is intended for research purposes only. This product is not intended to be used for therapeutic or diagnostic purposes in humans or animals.

New England Biolabs (NEB) is committed to practicing ethical science – we believe it is our job as researchers to ask the important questions that when answered will help preserve our quality of life and the world that we live in. However, this research should always be done in safe and ethical manner. Learn more.

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