A deoxyribonuclease from Chlamydomonas reinhardii. 1. Purification and properties.
A deoxyribonuclease has been purified more than 2000-fold from the green algae, Chlamydomonas reinhardii. The enzyme is most active on denatured DNA. Optimum activity is at pH 8.5, in 80 mM Tris-HCl buffer and 2 mM CaCl2. Other divalent cations can replace Ca2+ with varying lower efficiency. EDTA and inorganic phosphate are strongly inhibitory, while ATP and high concentrations of 2-mercaptoethanol are slightly inhibitory. The molecular weight is approximately 35 000, the Stokes radius is 2.7 nm, and the sedimentation coefficient 2.8 S. It is a single polypeptide chain, and the frictional ratio of 1.27 suggests it is only slightly asymetrical. The isoelectric point is 9.5. This enzyme has been termed exonuclease 1.
D000255:Adenosine Triphosphate / Q000494:pharmacology; D002118:Calcium / Q000494:pharmacology; D002413:Cations, Divalent; D002414:Cations, Monovalent; D002455:Cell Division; D002696:Chlamydomonas / Q000201:enzymology*; D003851:Deoxyribonucleases / Q000302:isolation & purification / Q000378:metabolism; D004492:Edetic Acid / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008623:Mercaptoethanol; D008970:Molecular Weight; D009691:Nucleic Acid Denaturation; D010710:Phosphates / Q000494:pharmacology; D011487:Protein Conformation; D013095:Spermidine / Q000494:pharmacology
D002413:Cations, Divalent; D002414:Cations, Monovalent; D010710:Phosphates; D008623:Mercaptoethanol; D000255:Adenosine Triphosphate; D004492:Edetic Acid; D003851:Deoxyribonucleases; D002118:Calcium; D013095:Spermidine