Multiple conformations of deoxyribonuclease A. Their separation at alkaline pH and low ionic strength in the presence of Ca2+.
Gel filtration on Sephadex G-100 at pH 9.0 in 1 mM Tris buffer produces denaturation and inactivation of pancreatic DNAase A. Limiting concentrations of Ca2+ in the suspension and elution buffer, reactivates some of the enzyme molecules in an amount proportional to the calcium added. Stable active and inactive forms were separated on Sephadex columns. A model for the conformational role of Ca2+ on DNAase A demonstrates that at least one Ca2+ is involved (Kapp = 8.3 . 10(-5) M) in the correct folding of the polypeptide chain. Na+ was unable to reactivate the enzyme.
D000468:Alkalies; D002118:Calcium; D003851:Deoxyribonucleases / Q000302:isolation & purification*; D006863:Hydrogen-Ion Concentration; D008956:Models, Chemical; D009994:Osmolar Concentration; D011487:Protein Conformation
D000468:Alkalies; D003851:Deoxyribonucleases; D002118:Calcium