DNA methylase from Pisum sativum.
DNA methylase activity was detected in nuclei from pea shoots. The enzyme can only be extracted by low-salt treatment if the nuclei are pretreated with micrococcal nuclease. Only a single enzyme was detected, and it was purified to a specific activity of 1620 units/mg of protein. It has an Mr of 160,000 on gel filtration and SDS/PAGE. Pea DNA methylase methylates cytosine in all four dinucleotides, and this is interpreted to show that it acts on CNG trinucleotides. Although it shows a strong preference for hemi-methylated double-stranded DNA, it is also capable of methylation de novo. Homologous DNA is the best natural substrate. In vitro the enzyme interacts with DNA to form a salt-resistant complex with DNA that is stable for at least 4 h.
Yesufu
H M
HM
Department of Biochemistry, University of Glasgow, U.K.
Hanley
A
A
Rinaldi
A
A
Adams
R L
RL
D001483:Base Sequence; D004247:DNA / Q000378:metabolism; D015257:DNA-Cytosine Methylases / Q000235:genetics / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D007887:Fabaceae / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development; D008970:Molecular Weight; D010946:Plants, Medicinal; D012965:Sodium Chloride / Q000494:pharmacology; D012995:Solubility; D013379:Substrate Specificity; D013997:Time Factors
D012965:Sodium Chloride; D004247:DNA; D015257:DNA-Cytosine Methylases