DESCRIPTION
Recombinant ribonuclease inhibitor effectively inhibits ribonuclease A type (ribonuclease A, B, and C) enzyme activity by binding non-covalently to RNase molecules at a 1:1 ratio. Recombinant ribonuclease inhibitor has the same inhibitory activity as the natural protein from human placenta but devoid of human DNA or proteins.

SOURCE
Recombinant strain of E. coli.

APPLICATIONS
● Protection of mRNA in cDNA synthesis.
● Improvement of protein translation performance.
● Increased yields and activity of polysomes.
● Improvement of in vitro virus replication.
● Improvement of RNA translation in homologous systems.

UNIT DEFINITION
One unit is defined as the amount of ribonuclease inhibitor required to inhibit by 50% the activity of 5ng of ribonuclease A.

STANDARD UNIT ASSAY CONDITIONS
Activity is measured by the inhibition of hydrolysis of cytidine 2',3'-cyclic monophosphate by ribonuclease A, where 200 units of ribonuclease inhibitor produces 50% inhibition of 1μg of ribonuclease A.

CONCENTRATION: 20-40 units/μl.

STORAGE CONDITIONS
20mM HEPES-KOH (pH7.6), 50mM KCl, 8mM DTT, and 50% glycerol. Store at -20℃ for frequent use and -70℃ for long term storage. If stored for long period of time or opened frequently, addition of DTT to 5mM final concentration into the reaction mixture is recommended to maintain optimal activity.

NOTE
Recombinant ribonuclease inhibitor is active over a broad pH range but requires a minimum of 1mM DTT to maintain activity.

REFERENCES
1. Blackburn, P. et al. (1977) J. Biol. Chem. 252, 5904.
2. Blackburn, P. and Jailkhani, B. L. (1979) J. Biol. Chem. 254, 12488.