DNA Polymerase-associated and autonomous vertebrate 3′→5′ exonuleases

Using methods of gel filtration and ultracentrifugation, cell-free extracts from 12 objects representing the main vertebrate representatives (bony fish, amphibian, reptiles, birds, mammals, including human) were studied. The enzyme activity of autonomous 3′→5′-exonucleases (AE) has been established to be 25–90% of the total 3′→5′ exonuclease activity of the extracts. A part of the AE is revealed in a zone of the DNA polymerases of the α-family and can be separated by changing Chromatographic conditions or by repeated fractionation. The high activity of AE allows suggesting their substantial participation in the replicative correction of the DNA-poly-merase errors as well as in the postreplicative correction of the heteroduplexes in the vertebrate DNA.