Purification of the human O6-methylguanine-DNA methyltransferase and uracil-DNA glycosylase, the latter to apparent homogeneity.
Uracil-DNA glycosylase, the enzyme that catalyzes the release of free uracil from single-stranded and double-stranded DNA, has been purified 26,600-fold from HeLa S3 cell extracts. The enzyme preparation was essentially homogeneous as judged by sodium dodecyl sulfate/polyacrylamide gel electrophoresis. The native enzyme is a small monomeric protein of molecular mass 29 kDa. A minor uracil-DNA glycosylase preparation was also obtained in the final chromatographic step. This preparation is homogeneous with a molecular mass of 29 kDa and may represent the mitochondrial enzyme. This report also presents a 700-fold purification of HeLa S3 cell O6-methylguanine-DNA methyltransferase. The glycosylase and methyltransferase showed very similar chromatographic properties. The report indicates that the lability of the methyltransferase upon purification may be a consequence of the total separation of the two DNA repair enzymes or of the possibility that some other stabilizing factor is involved.
Myrnes
B
B
Department of Biochemistry, University of Tromsø, Norway.
Wittwer
C U
CU
D002848:Chromatography, DEAE-Cellulose; D002850:Chromatography, Gel; D045647:DNA Glycosylases; D004591:Electrophoresis, Polyacrylamide Gel; D006367:HeLa Cells; D006801:Humans; D008780:Methyltransferases / Q000302:isolation & purification*; D009699:N-Glycosyl Hydrolases / Q000302:isolation & purification*; D019853:O(6)-Methylguanine-DNA Methyltransferase; D011072:Poly U / Q000302:isolation & purification; D051981:Uracil-DNA Glycosidase
D011072:Poly U; D008780:Methyltransferases; D019853:O(6)-Methylguanine-DNA Methyltransferase; D045647:DNA Glycosylases; D009699:N-Glycosyl Hydrolases; D051981:Uracil-DNA Glycosidase