Mitochondrial DNA polymerase, deoxyribonuclease and ribonuclease H activities from brain of chick embryo.
R-DNA polymerase, D-DNA polymerase, DNase and RNase H activities in mitochondria from chick embryonic brain were studied by ion-exchange chromatography. Two main fractions were separated according to their chromatographic behaviour: a fraction M Ib which is eluted with the washing buffer from two successive DEAE-cellulose columns and a fraction M IV which is eluted at 400 mM KC1 from a phosphocellulose column. Although the two fractions contain both the DNA polymerase and the degrading activities, all the specific activities are higher in fraction M IV than in fraction M Ib. Heat inactivation experiments have shown that R-DNA polymerase is inactivated in both fractions, whereas RNase H and DNase are not affected. Thus, degrading activities and R-DNA polymerase activity seem to be catalyzed by different molecular entities. However the fact that in most cases these activities co-chromatograph suggests that the corresponding molecules form rather stable complexes.
D000818:Animals; D001921:Brain / Q000201:enzymology*; D002642:Chick Embryo; D002848:Chromatography, DEAE-Cellulose; D002852:Chromatography, Ion Exchange; D004254:DNA Nucleotidyltransferases / Q000302:isolation & purification / Q000378:metabolism*; D003851:Deoxyribonucleases / Q000302:isolation & purification / Q000378:metabolism*; D007700:Kinetics; D008928:Mitochondria / Q000201:enzymology*; D012260:Ribonucleases / Q000302:isolation & purification / Q000378:metabolism*; D013698:Templates, Genetic
D004254:DNA Nucleotidyltransferases; D003851:Deoxyribonucleases; D012260:Ribonucleases