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ISOLATION AND CHARACTERIZATION OF A MARSUPIAL DNA PHOTOLYASE
Author(s) -
Sabourin Carol L. K.,
Ley Ronald D.
Publication year - 1988
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.1988.tb02770.x
Subject(s) - monodelphis domestica , photolyase , pyrimidine dimer , dna , biology , biochemistry , enzyme , microbiology and biotechnology , chemistry , opossum , dna damage , dna repair , anatomy
— Post UV‐B(280–320 nm) exposure to UV‐A(320–400 nm) reverses pyrimidine dimers in the epidermal DNA of the South American opossum Monodelphis domestica [Ley, R. D. (1984) photorepair of pyrimidine dimers in the epidermis of the marsupial Monodelphis domestica. Photochem. Photobiol . 40 ,141–143.] To demonstrate that the observed photorepair is mediated by an enzyme, we have isolated a DNA photolyase from the opossum. DNA photolyase from liver was purified 3000‐fold by ammonium sulfate fractionation and phenylsepharose, hydroxylapatite, DEAE‐cellulose and DNA‐cellulose column chromatography. Heat denaturation (60°C for 4 min) completely eliminated the photoreactivating activity. The enzyme was active in the pH range of 5.5 to 8.5 with a pH optimum of 7.5. The enzyme has an apparent molecular weight of 32 000 under nondenaturing conditions. The activity of the enzyme was not affected by sodium chloride up to 250 m M . The action spectrum for the purified DNA photolyase showed activity in the range of325–475 nm with peak actvity at 375 nm.