Inhibition of DNA processing in heavy metal carcinogenesis - Essay Example

Nonetheless, although it has been noted that some heavy metals may inhibit SSB (single strand break) rejoining, the effects on single strand break end-processing enzymes has never previously been investigated. First, an analysis on the DNA replication as a result of topo-1 enzyme will be done. This will show how topo-1 enzyme is responsible for winding of DNA structures. A picture analysis will be included to show evidence of the process. As mentioned earlier, different heavy metals have effects on the living organism’ DNA.

The metals will be discussed together with their effects. This paper also explores inhibition of superoxide dismutases. This enzyme catalysis the dismutation of extremely reactive superoxide ions to generate hydrogen peroxide and numerous lines of evidence propose that these enzymes play significant part in the development and also response to treatment of cancers. These are enzymes that control under-winding and over-winding of DNA. DNA winding comes from the intertwined nature of its double-helical structure.

For instance, during replication of DNA, DNA is overwound before a replication fork. When it is not controlled, it will eventually lead to a halt in DNA replication. A similar process is observed during transcription. To overcome the topological problems resulting from the double helix, topoisomerases are bound to single or double stranded DNA and cut the phosphate spine of the DNA. This untangles the DNA releasing the DNA spine again. Since the chemical composition of the DNA remains the same, the untangled DNAs are chemical isomers.

Therefore, topoisomerases are isomerase enzymes which work on the DNA topology. The N-terminal domain is then preceded by a highly conserved, 421 amino acid core domain that contains all of the catalytic residues except the active site tyrosine. A protease-sensitive and poorly conserved linker domain