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DNA polymerase activities of human milk

B I Gerwin, P S Ebert, H C Chopra

    Science (New York, N.Y.)
    |April 15, 1973
    PubMed

    Insights

    Human milk contains DNA polymerases with unique properties. While one enzyme resembles RNA tumor virus enzymes in template preference, its chromatographic behavior differs, and its activity doesn't correlate with cancer family history.

    Area of Science:

    • Biochemistry
    • Molecular Biology
    • Human Milk Research

    Background:

    • Human milk is a source of various biological molecules.
    • DNA polymerases are crucial enzymes involved in DNA replication and repair.
    • Reverse transcriptase activity has been investigated in relation to cancer.

    Purpose of the Study:

    • To partially purify and characterize DNA polymerases from human milk.
    • To compare the properties of human milk DNA polymerases with those of RNA tumor viruses.
    • To investigate potential correlations between "reverse transcriptase" activity in human milk and cancer family history.

    Main Methods:

    • Partial purification of DNA polymerases using phosphocellulose chromatography.
    • Enzyme activity assays using different template types (DNA, polyriboadenylate-oligodeoxythymidylate hybrid).
    • Detection of "reverse transcriptase" activity using three distinct methods.

    Main Results:

    • A DNA polymerase was purified from human milk.
    • This enzyme showed a preference for a polyriboadenylate-oligodeoxythymidylate template over DNA, similar to RNA tumor virus enzymes.
    • The purified polymerase exhibited different chromatographic behavior compared to RNA tumor virus enzymes.
    • No correlation was found between detected "reverse transcriptase" activity and the donor's family history of cancer.

    Conclusions:

    • Human milk contains DNA polymerases with characteristics distinct from those of RNA tumor viruses.
    • The presence and activity of these polymerases in human milk do not appear to be linked to familial cancer predisposition based on the tested methods.

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