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Key Documents

SRP2035

Sigma-Aldrich

Topo I (Y723F) (mt Y723F) human

recombinant, expressed in insect cells, ≥80% (SDS-PAGE)

Synonym(s):

TOPI

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About This Item

UNSPSC Code:
12352202
NACRES:
NA.26

biological source

human

recombinant

expressed in insect cells

assay

≥80% (SDS-PAGE)

form

frozen liquid

mol wt

~92.4 kDa

packaging

pkg of 5 μg

storage condition

avoid repeated freeze/thaw cycles

concentration

1000 μg/mL

color

clear colorless

NCBI accession no.

UniProt accession no.

shipped in

dry ice

storage temp.

−70°C

Gene Information

human ... TOP1(7150)

Biochem/physiol Actions

Human DNA topoisomerase I is the best studied of the DNA topoisomerase family. It catalyzes the relaxation of both positive and negative supercoiled DNAs without the requirement of energy. In addition to DNA replication and transcriptional activation, DNA topoisomerase I also plays a major role in pre-mRNA splicing, cell cycle and other gene regulatory pathways during cell growth and development. Tyrosine 723 was identified as an active site for the DNA binding activity of DNA topoisomerase I. The covalent intermediate of topo I and DNA complex includes nucleophilic attack by the O4-oxygen of tyrosine 723 on a phosphester linkage in the DNA. Mutation from tyrosine to phenylalanine at position 723 preferentially binds the supercoiled DNA rather than relaxed DNA in the mixture of supercoiled and relaxed DNAs. But mutation at tyr723 neither affects its kinase activity that phosphorylates splicing factors of SR protein family nor its transcription activity of class II genes in vitro.

Physical form

Clear and colorless frozen liquid solution

Preparation Note

Use a manual defrost freezer and avoid repeated freeze-thaw cycles. While working, please keep sample on ice.

Storage Class

10 - Combustible liquids

wgk_germany

WGK 1

flash_point_f

Not applicable

flash_point_c

Not applicable


Certificates of Analysis (COA)

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J J Champoux
The Journal of biological chemistry, 256(10), 4805-4809 (1981-05-25)
Conditions which result in DNA strand breakage by the rat liver DNA nicking-closing enzyme lead to the covalent attachment of the 3'-end of the broken strand to the enzyme. Treatment of this complex with pancreatic DNase leaves a residue of
DNA topoisomerase poisons as antitumor drugs.
L F Liu
Annual review of biochemistry, 58, 351-375 (1989-01-01)
J J Champoux
Annual review of biochemistry, 70, 369-413 (2001-06-08)
DNA topoisomerases solve the topological problems associated with DNA replication, transcription, recombination, and chromatin remodeling by introducing temporary single- or double-strand breaks in the DNA. In addition, these enzymes fine-tune the steady-state level of DNA supercoiling both to facilitate protein

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