Abstract
The 3' AP endonucleases (class I) are said to hydrolyze the phosphodiester bond 3' to AP sites yielding 3'-OH and 5'-phosphate ends; on the other hand, the resulting 3' terminal AP site is not removed by the 3'-5' exonuclease activity of the Klenow fragment [1]. We show that AP sites in DNA are easily removed by the 3'-5' exonuclease activity of the Klenow fragment and that they are excised as deoxyribose-5-phosphate. It is suggested that the 3' AP endonucleases are perhaps not the hydrolases they are supposed to be.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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DNA / metabolism
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DNA Polymerase I / metabolism*
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DNA-(Apurinic or Apyrimidinic Site) Lyase
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Deoxyribonuclease IV (Phage T4-Induced)
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Endodeoxyribonucleases / metabolism*
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Escherichia coli / enzymology*
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Escherichia coli Proteins*
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Phosphates / metabolism
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Phosphorus Radioisotopes
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Substrate Specificity
Substances
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Escherichia coli Proteins
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Phosphates
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Phosphorus Radioisotopes
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DNA
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DNA Polymerase I
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Endodeoxyribonucleases
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Deoxyribonuclease IV (Phage T4-Induced)
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endonuclease IV, E coli
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DNA-(Apurinic or Apyrimidinic Site) Lyase