Unit Definition:One unit is the amount of enzyme required to inhibit by 50% the activity of 5ng of RNase A at 25°C (This inhibitor activity is determined by its ability to inhibit hydrolysis of cyclic 2', 3'-CMP by RNase A).
Quality Control:Nuclease activity was not detected in any of the following cases, as judged from the intact gel electrophoresis:1. After incubation of 1ug of λ DNA-Hind III fragments with 300 units of enzyme for 24 hours at 37°C2. After incubation of 1ug of pBR322 DNA with 300 units of enzyme for 24 hours at 37°C3. Migrates as a single band of 50 kd in SDS-polyacrylamide gel electrophoresis.
Note: Enzyme inhibits in a wide pH range, but most strongly at pH 7-8. Requires DTT of at least 1 mM to be active.
Storage and Stability:May be stored at 4°C for short-term only. Aliquot to avoid repeated freezing and thawing. Store at -20°C. Aliquots are stable for at least 6 months at -20°C. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap. Further dilutions can be made in assay buffer.
