Embryonic chicken brain and mouse neuroblastoma cells N1E-115 and N-18 contain an inhibitor of acid deoxyribonuclease.

Activity of a trypsin-sensitive acid deoxyribonuclease (DNase) inhibitor has been detected in 13- to 21-day-old embryonic chicken brains and in clonal lines of neuroblastoma cells (adrenergic, N1E-115, and neurotransmitter-inactive, N-18) grown for 48 hr after subculture. The activities of purified porcine and bovine spleen DNases were inhibited 60--75% in the presence of the inhibitor, whereas less than 10% inhibition was observed with purified pancreatic DNase. Activities of an acidic DNase and its inhibitor reached maxima in 21-day-old embryonic chicken brain.