Product Description
The topology of the DNA is a crucial issue in different biological processes like recombination, replication, transcription, and chromatin remolding. DNA topoisomerases are enzymes that control the amount of supercoiling in DNA. Without topoisomeras, DNA cannot replicate normally. The protein family of DNA topoisomerases is divided into two types (type I and II) based on their mechanism and physical properties. While the type I topoisomerases are monomeric and do not require ATP, the type II contain multi-subunits and depend on ATP for their activity. The type I enzymes include eukaryotic and bacterial topoisomerase I and III. The type II enzymes include bacterial DNA gyrase and topoisomerase IV and the eukaryotic topoisomerase II. Type I enzymes introduce transient single strand breaks in DNA, while type II enzymes produce transient double strand breaks in the DNA. Human DNA Topoisomerase I belongs to the subtype IB enzymes. The protein has four distinct domains. The N-terminal 214 amino acids are dispensable for relaxation activity and constitutes a hydrophilic and highly protease sensitive region of the protein. There are four nuclear localization signals in the N-terminal domain. The second domain is a core domain of 421 amino acids that is responsible for the single break in the DNA. Recently it was reported that DNA topoisomerase I is involved in modulation of RNA and is present in retroviral particles (like HIV1). Furthermore, the enzyme enhances HIV-1 cDNA production in reverse transcription assays. Topo II plays important roles in synthesis and transcription of DNA as well as chromosomal segregation during mitosis. It is reported to be a sensitive and specific marker of late S-, G2- & M-phases in transformed and developmentally regulated normal cells Top II is also implicated in drug resistance of tumor cells. Applications: Suitable for use in ELISA and Western Blot Other applications not tested. Recommended Dilution: ELISA: 0.1-1ug/ml, Control peptide can be used to coat plates at 1ug/ml. See T8065-13G. Western Blot: 2-10ug/ml is recommended for Western. Human Raji cells topoisomerase II alpha is ~170kD. Optimal dilutions to be determined by the researcher. Storage and Stability: Lyophilized powder may be stored at -20C. Stable for 12 months at -20C. Reconstitute with sterile ddH2O or PBS. Aliquot to avoid repeated freezing and thawing. Store at -20C. Reconstituted product is stable for 12 months at -20C. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap. Further dilutions can be made in assay buffer.
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