Isolation of DNA methyltransferase from plants
DNA methyltransferases (DMT) were isolated from nuclei of cauliflower, soybean, and pea by extraction with 0.35 M NaCl. Assays were performed on hemimethylated Micrococcus luteus DNA or on M. luteus DNA to test for maintenance or de novo methylase activity, respectively. Fully methylated DNA was used as a substrate to determine background levels of methylation. Based on these tests, yields of maintenance DMT activity in the crude extract from pea hypocotyl, soybean hypocotyl, and cauliflower inflorescence were 2.8, 0.9, and 1.6 units per g wet tissue (one unit equals 1 pmol of methyl from (/sup 3/H)AdoMet incorporated into acid precipitable material per h at 30/sup 0/). Two peaks of DMT activity were detected in the soybean nuclear extract following phosphocellulose chromatography. One eluted at 0.4 M and the other at 0.8 M KCl. With both fractions maintenance activity was approximately 2 times that of the de novo activity. Using gel filtration the DMT eluted at 220,000 Daltons. The optimal pH for activity was between 6.5 and 7.0, and the optimal temperature was 30/sup 0/.
- Research Organization:
- Dept. of Agriculture, New Orleans, LA
- OSTI ID:
- 6023307
- Report Number(s):
- CONF-870644-
- Journal Information:
- Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States), Vol. 46:6; Conference: 78. annual meeting of the American Society of Biological Chemists conference, Philadelphia, PA, USA, 7 Jun 1987
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
DNA
METHYLATION
TRANSFERASES
ENZYME ACTIVITY
BRASSICA
CELL NUCLEI
CHROMATOGRAPHY
GLYCINE HISPIDA
MICROCOCCUS LUTEUS
PH VALUE
PISUM
TEMPERATURE DEPENDENCE
TRACER TECHNIQUES
TRITIUM COMPOUNDS
BACTERIA
CELL CONSTITUENTS
CHEMICAL REACTIONS
ENZYMES
FOOD
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
LEGUMINOSAE
MICROCOCCUS
MICROORGANISMS
NUCLEIC ACIDS
ORGANIC COMPOUNDS
PLANTS
RHIZOBIUM
SEPARATION PROCESSES
VEGETABLES
550201* - Biochemistry- Tracer Techniques