Abstract
A mouse repair enzyme having priming activity on bleomycin-damaged DNA for DNA polymerase was purified to apparent homogeneity and characterized. The enzyme extracted from permeabilized mouse ascites sarcoma (SR-C3H/He) cells with 0.2 M potassium phosphate buffer (pH 7.5) was purified by successive chromatographies on phosphocellulose, DEAE-cellulose, phosphocellulose (a second time), Sephadex G-100, single-stranded DNA cellulose and hydroxyapatite. The purified enzyme has an Mr of 34,000 as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Enzymatical studies indicated that it is a multifunctional enzyme having exonuclease, apurinic/apyrimidinic endonuclease and phosphatase activities, similar to Escherichia coli exonuclease III. This enzyme is tentatively designated as APEX nuclease for apurinic/apyrimidinic endonuclease and exonuclease activities. The amino acid composition, amino-terminal amino acid sequence and an internal amino acid sequence of APEX nuclease are determined.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Amino Acid Sequence
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Animals
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Bleomycin / toxicity
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Carbon-Oxygen Lyases*
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Chromatography, Liquid
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DNA / drug effects
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DNA Repair*
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DNA-(Apurinic or Apyrimidinic Site) Lyase
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Deoxyribonuclease IV (Phage T4-Induced)
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Electrophoresis, Polyacrylamide Gel
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Endodeoxyribonucleases / isolation & purification*
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Endodeoxyribonucleases / metabolism*
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Escherichia coli Proteins*
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Exodeoxyribonucleases / isolation & purification*
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Exodeoxyribonucleases / metabolism
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Exonucleases / metabolism*
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Mice
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Molecular Sequence Data
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Multienzyme Complexes / isolation & purification*
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Multienzyme Complexes / metabolism
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Phosphoric Monoester Hydrolases / metabolism
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Sequence Homology, Nucleic Acid
Substances
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Escherichia coli Proteins
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Multienzyme Complexes
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Bleomycin
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DNA
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Endodeoxyribonucleases
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Exodeoxyribonucleases
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Exonucleases
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Deoxyribonuclease IV (Phage T4-Induced)
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endonuclease IV, E coli
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Phosphoric Monoester Hydrolases
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Carbon-Oxygen Lyases
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Apex1 protein, mouse
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DNA-(Apurinic or Apyrimidinic Site) Lyase