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Literature summary for 5.6.2.1 extracted from

  • Chan, A.; Chang, W.; Chen, L.; Lee, C.; Chen, C.; Lin, C.; Hwang, J.
    Evodiamine stabilizes topoisomerase I-DNA cleavable complex to inhibit topoisomerase I activity (2009), Molecules, 14, 1342-1352.
    View publication on PubMedView publication on EuropePMC
Search for more literature for 5.6.2.1

Inhibitors

Inhibitors Comment Organism Structure
(S)-camptothecin
-
 Homo sapiens
evodiamine EVO, an alkaloidal compound isolated from Evodia rutaecarpa, is able to inhibit supercoiled plasmid DNA relaxation catalyzed by TopI by stabilizing topoisomerase I-DNA cleavable complex Homo sapiens
additional information evodiamine is slightly less cytotoxic than campothecin against breast MCF-7 carcinoma cells Homo sapiens

Metals/Ions

Metals/Ions Comment Organism Structure
Mg2+
-
 Homo sapiens

Natural Substrates/ Products (Substrates)

Natural Substrates Organism Comment (Nat. Sub.) Natural Products Comment (Nat. Pro.) Rev. Reac.
additional information Homo sapiens reversible reaction. TopI produces a single strand break in DNA, allowing relaxation of DNA during its replication. The single strand break is then religated, thus restoring the DNA double strands. The enzymatic mechanism involves two sequential transesterification reactions. The cleavage reaction involves the active site Tyr723 acting as a nucleophile. A phenolic oxygen attacks a DNA phosphodiester bond, forming an intermediate in which the 3' end of the broken strand is covalently attached by an O4-phosphodiester bond to TopI tyrosine. The religation step consists of transesterification involving a nucleophilic attack by the hydroxyl oxygen at the 5' end of the broken strand. The equilibrium constant of the breakage and closure reactions is close to unity ?
-
 ?

Organism

Organism UniProt Comment Textmining
Homo sapiens
-
-
-

Source Tissue

Source Tissue Comment Organism Textmining
MCF-7 cell
-
 Homo sapiens
-

Substrates and Products (Substrate)

Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
additional information reversible reaction. TopI produces a single strand break in DNA, allowing relaxation of DNA during its replication. The single strand break is then religated, thus restoring the DNA double strands. The enzymatic mechanism involves two sequential transesterification reactions. The cleavage reaction involves the active site Tyr723 acting as a nucleophile. A phenolic oxygen attacks a DNA phosphodiester bond, forming an intermediate in which the 3' end of the broken strand is covalently attached by an O4-phosphodiester bond to TopI tyrosine. The religation step consists of transesterification involving a nucleophilic attack by the hydroxyl oxygen at the 5' end of the broken strand. The equilibrium constant of the breakage and closure reactions is close to unity Homo sapiens ?
-
 ?
additional information TopI catalyzes supercoiled plasmid DNA relaxation Homo sapiens ?
-
 ?

Synonyms

Synonyms Comment Organism
TopI
-
 Homo sapiens
Topoisomerase I
-
 Homo sapiens

Temperature Optimum [°C]

Temperature Optimum [°C] Temperature Optimum Maximum [°C] Comment Organism
37
-
 assay at Homo sapiens

pH Optimum

pH Optimum Minimum pH Optimum Maximum Comment Organism
7.9
-
 assay at Homo sapiens

IC50 Value

IC50 Value IC50 Value Maximum Comment Organism Inhibitor Structure
0.00323
-
-
 Homo sapiens (S)-camptothecin
0.00602
-
-
 Homo sapiens evodiamine

General Information

General Information Comment Organism
physiological function DNA topoisomerase enzymes regulate the topological state of DNA that is crucial for initiation and elongation during DNA synthesis Homo sapiens