Human TDP-1

DTopoGEN provides purified Human Tyrosyl DNA Phosphodiesterase (Tdp1) purified to homogeneity to a single 68 kDa band on SDS-PAGE.  Tdp1 is catalytically active and will remove a terminal 3’ phosphotyrosyl group from a specifically designed oligo target site (oligo-Tyr).  Additionally, TopoGEN scientists have demonstrated that Tdp1 will release topo I covalently attached to genomic DNA isolated from cells treated with camptothecin using TopoGEN’s In Vivo Link Kit (TG1021).  Tdp1 is thought to be important in repair of topo/DNA adducts that form following topo-active drug therapy; therefore, there is considerable interest in identifying drugs that target Tdp1.  Such drugs may work well in combination with topo targeting strategies.

Figure 1.  SDS-PAGE of TopoGEN Purified Tdp1.  The gel was intentionally overloaded with 20ug of protein to reveal minor breakdown products.

Unit Defintion:
One unit of Tdp1 can release the terminal Tyrosine from 20 ng of substrate (oligo-Tyr) in 30 min at 37° C.

Tdp1 Reaction:
Release of topo I from the covalent complex is shown below.

Tdp-1 Activity

Tdp1 Assays:
Biochemical assays for Tdp1 can be carried out using an oligo nucleotide with a 3’ terminal tyrosine residue.  Release of tyrosine from a 5’ 32P end labeled oligo is easily measured using a denaturing polyacrylamide gel or DNA sequencing gels.  TopoGEN Provides a kit for Tdp1 assay (TG1004) that has key reagents and controls/protocols for setting up a complete assay for Tdp1.

This product is shipped on wet ice and should be stored at – 20°C.