Mesure Quantitative de L'Activité de la Desoxyribonuclease Plasmatique et de Son Inhibition Par le Complexe Daunorubicine‐ADN

A sensitive, fast and quantitative method was described to estimate plasma deoxyribonuclease (DNase) activity. This method was using125I DNA as substrate and the activity of the enzyme was measured by the increase of radioactivity in the TCA‐soluble fraction. The method was enough sensitive to detect the activity of about long of pure DNase I. The coefficient of variation was always lower than 10% at the weakest activity and lower than 2% at higher activities. Experimental results did confirm the weak activity of human plasma DNase, which was about 5‐fold lower than the rabbit's one. In presence of a daunorubicin‐DNA complex with a molar ratio of 20, this activity was inhibited by half.