PURIFICATION AND CHARACTERIZATION OF A GAMMA-LIKE DNA-POLYMERASE FROMCHENOPODIUM-ALBUM L

A DNA polymerase activity from mitochondria of the dicotyledonous angi osperm Chenopodium album L. was purified almost 9000 fold by successiv e column chromatography steps on DEAE cellulose, heparin agarose and s sDNA cellulose. The enzyme was characterized as a gamma-class polymera se, based on its resistance to inhibitors of the nuclear DNA polymeras e alpha and its preference for poly(rA).(dT)12-18 over activated DNA i n vitro. The molecular weight was estimated to be 80,000 - 90,000. A 3 ' to 5' exonuclease activity was found to be tightly associated with t he DNA polymerase activity through all purification steps. This is the first report of an association between a DNA polymerase and an exonuc lease activity in plant mitochondria.