title: DNA methylases separated through the HeLa cell cycle methodology show allosteric properties.
abstract: Two DNA methylases (DNAmets) can be separated through the cell cycle. The first appears as a minor peak in G1, the second as a major peak in S. Both enzymes protect from HpaII a plasmid (H31), constructed with the pBR322 vector (4.3 kbp) and the inverted A gamma fragment of the human globin gene (3.5 kbp), inserted at its HindIII site (the vector carries several HpaII sites, the insert only one HpaII site). DNAmets G1 and S show distinct Km values and different kinetics vs the ionic strength of the medium, while their Michaelis-Menten and Lineweaver-Burk plots are sigmoidal and hyperbolical curves, respectively. This is the first suggestion about the allosteric nature of the eukaryotic DNAmet system.
mesh_terms: D000494:Allosteric Regulation; D002453:Cell Cycle; D004248:DNA (Cytosine-5-)-Methyltransferases / Q000378:metabolism*; D006367:HeLa Cells / Q000166:cytology / Q000201:enzymology; D006801:Humans; D007700:Kinetics
chemical_list: D004248:DNA (Cytosine-5-)-Methyltransferases