On the mechanism of metal activation of deoxyribonuclease I

摘要: Abstract 1. The activation of deoxyribonucleasc I (DNase I) by Mg ++ , Mn and Ca has been studied at 27 °C., an ionic strength 0.15, a pH 7.5 - 7.2. Alone, the metals rank us activators in order > ⪢ . 2. Activity presence or shown to require formation “metallosubstrate.” 3. In study pairs these metals, was found be potent Synergist Mg-activated reaction, increasing maximum rate more than threefold, give comparable that given alone. Several possible explanations are suggested. 4. A rapid method is described for standardizing solutions large number bivalent metal salts. 5. pitfalls DNase assay methods discussed modifications 6. inhibition citrate deprecated; ethylenediaminetetraacetic acid suggested replace citrate. 7. dissociation constant determined 1.90 ± 0.13 × 10 −4 using ion-exchange radioisotope method.