The specificity and catalytic properties of Alu I methylase

• Main Authors: Han, Moon H., Yoon, Ho Sup, Suh, Hyang, Kim, Kitae, Yoo, Ook Joon
• Other Authors: School of Biological Sciences
• Format: Article
• Language: English
• Published: 2012
• Subjects: DRNTU::Science::Biological sciences
• Online Access: https://hdl.handle.net/10356/95342; http://hdl.handle.net/10220/8714; http://www.jbmb.or.kr/jbmbonline/18_1/list.html
• Institution: Nanyang Technological University

The specific methylation site for Alu I methylase was the cytosine nucleotide in Alu I sequence. The position of the methylated cytosine nucleotide was determined by the chemical cleavage reactions of the Maxam-Gilbert DNA sequencing procedure. As expected, the methylated cytosine nucleotide bands were disappeared on C+ T and C lanes on 12% sequencing gels. Alu I methylase was maximally active at near pH 7.5 in the presence of 50 mM NaCl. The methylase did not require Mg++ for activity, and obeyed Michaelis-Menten Kinetics with respect to both AdoMet and DNA. At 37°C, the Km for AdoMet was 0.44 μM, that for the Alu I site of pBR 322 DNA was 4.03 nM, and the corresponding turnover numbers were 1.83 methyl transfer per minute per monomer and 1.61 transfers per minute per monomer, respectively.