Retention of activity of solutions of pancreatic deoxyribonuclease after freezing and thawing.

Abstract

Solutions of deoxyribonuclease containing 1.25 mg of enzyme per ml of 0.003 M MgSO4 were placed in small, sealed containers in a deep-freeze cabinet (ca – 20°C) and stored for periods of time ranging from 15 min to 35 days. Upon removal, each sample was thawed and then tested for its capacity to reduce Feulgen stain-ability in sections of onion root tips. No appreciable loss in enzymatic activity was effected by the freezing-thawing process. The method is recommended for experimental procedures extending over a period of days in which a constant supply of enzyme of known potency and specificity of action is required.