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Biochem Biophys Res Commun 37: 982-9 (1969)[70065820]
DNA polymerase from Escherichia coli was cleaved by limited
proteolytic action into two fragments of 76,000 and 34, 000 molecular
weight. The cleaved enzyme is still an active polymerase but has a
reduced 5'=>3' nuclease activity The fragments were separated by
gel filtration. The isolated larger fragment retains the polymerizing
activity and the 3'=>5' nuclease activity present in the native
enzyme, but not the 5'=>3' nuclease. This specific proteolytic
cleavage was catalyzed most effectively by an extract from Bacillus
subtilis or by trypsin.