Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.25.1 (deoxyribonuclease)
 1,471 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The activities of three human DNA metabolizing enzymes--uracil-DNA glycosylase, apurinic/apyrimidinic(AP)-DNA binding protein (an AP-DNA endonuclease) and the major cellular deoxyribonuclease (presumably DNase III and/or DNase IV)--were measured in logarithmic growing (diploid non-established) fibroblast strains, tumor-derived cell lines and SV40-transformed cell lines. The levels of activity of uracil-DNA glycosylase and DNase were increased, on average, 5- to 6-fold in tumor cell lines and 10-fold in SV40-transformed cell lines compared to those observed in normal fibroblast strains. AP-DNA binding activity was only 2- to 3-fold higher in both tumor-derived and SV40-transformed cell lines. Measurements in serum-deprived (and hence growth-retarded) SV40-transformed cells indicated that the observed increase in enzyme activity was only partially due to a higher proportion of S-phase cells in the rapidly growing transformed lines. Cell extract mixing experiments indicated that the relatively low levels of activity of the three enzymes in normal fibroblasts could not be ascribed to the presence of an inhibitory factor(s) in the crude extract.
 ...
PMID:Increased uracil-DNA glycosylase, AP-DNA binding protein and deoxyribonuclease activities in tumor and SV40-transformed cell lines of human origin. 168 17

Ultraviolet (UV) irradiation induces predominantly cyclobutane and (6-4) pyrimidine dimer photoproducts in DNA. Several mechanisms for repairing these mutagenic UV-induced DNA lesions have been identified. Nucleotide excision repair is a major pathway, but mechanisms involving photolyases and DNA glycosylases have also been characterized. Recently, a novel UV damage endonuclease (UVDE) was identified that initiates an excision repair pathway different from previously established repair mechanisms. Homologues of UVDE have been found in eukaryotes as well as in bacteria. In this report, we have used oligonucleotide substrates containing site-specific cyclobutane pyrimidine dimers and (6-4) photoproducts for the characterization of this UV damage repair pathway. After introduction of single-strand breaks at the 5' sides of the photolesions by UVDE, these intermediates became substrates for cleavage by flap endonucleases (FEN-1 proteins). FEN-1 homologues from humans, Saccharomyces cerevisiae, and Schizosaccharomyces pombe all cleaved the UVDE-nicked substrates at similar positions 3' to the photolesions. T4 endonuclease V-incised DNA was processed in the same way. Both nicked and flapped DNA substrates with photolesions (the latter may be intermediates in DNA polymerase-catalyzed strand displacement synthesis) were cleaved by FEN-1. The data suggest that the two enzymatic activities, UVDE and FEN-1, are part of an alternative excision repair pathway for repair of UV photoproducts.
 ...
PMID:Processing of UV damage in vitro by FEN-1 proteins as part of an alternative DNA excision repair pathway. 1020 Jan 69