Clinical investigation of serum deoxyribonuclease: I. Analysis of serum deoxyribonuclease activity in comparison with normal and after endoscopic retrograde pancreatography.

Serum Deoxyribonuclease (DNase) micro-assay method was developed using 32P-labelled E. coli DNA as substrate. The serum DNase showed maximum activity at pH 7.5. It required Mg+ for activity, and was inhibited by EDTA or EGTA. The enzyme was also inhibited by actin (60-65%) or bovine pancreatic DNase I antibody (40-45%). The serum DNase activity was markedly increased following endoscopic retrograde pancreatography (ERP) examination. These results imply that serum DNase activity is mostly at least 60-65% pancreatic DNase I.