Effect of Mg2+ and Mn2+ on hydrolysis of calf thymus DNA by pancreatic deoxyribonuclease I.
Divalent cations are activators for DNA hydrolysis by pancreatic deoxyribonuclease I. Apparent Vm and Km changes have been studied in presence of Mn2+ or Mg2+. The activation process modifies both Vm and Km, their relationship with Mg2+ or Mn2+ being a linear one. Deoxyribonucleotides inhibit the DNA hydrolysis, whether Mg2+ or Mn2+ is the activator; the purine deoxyribonucleotides are more effective as inhibitors than the pyrimidine ones. The effect of some derivatives of adenine has been studied: the inhibition is maximum with 5'-dAMP and minimum with adenine or adenosine. A kinetic mechanism of enzymatic activation by Mn2+ or Mg2+ is discussed.
D000227:Adenine Nucleotides / Q000494:pharmacology; D000818:Animals; D002417:Cattle; D004247:DNA; D003850:Deoxyribonuclease I; D003851:Deoxyribonucleases / Q000378:metabolism*; D003854:Deoxyribonucleotides / Q000494:pharmacology; D004720:Endonucleases / Q000378:metabolism*; D007700:Kinetics; D008274:Magnesium / Q000494:pharmacology*; D008345:Manganese / Q000494:pharmacology*; D010179:Pancreas / Q000201:enzymology*; D013950:Thymus Gland / Q000032:analysis
D000227:Adenine Nucleotides; D003854:Deoxyribonucleotides; D008345:Manganese; D004247:DNA; D003851:Deoxyribonucleases; D004720:Endonucleases; D003850:Deoxyribonuclease I; D008274:Magnesium