Shop All Molecular Biology Enzyme Inhibitors

Ribonuclease Inhibitor, Cloned (Invitrogen™)

Ribonuclease Inhibitor, Cloned is a potent non-competitive inhibitor of neutral pancreatic ribonucleases.

Cell-free translation systems (1). Reverse transcription of mRNA (2).

Recombinant, purified from E. coli.

Performance and Quality Testing:
No detectable contaminating activity is observed in DNA nicking, ribonuclease, and protease assays.

Unit Definition:
One unit inhibits 5 ng RNase A by 50% using cytidine 2´, 3´ cyclic monophosphate (cCMP) as the substrate (3).

Ambion™ RNase Inhibitor, cloned, 40 U/µL (Invitrogen™)

Ambion® RNase Inhibitor, a recombinant human protein produced in E. coli, is a potent inhibitor of neutral pancreatic RNase A type enzymes. The mode of inhibition is noncompetitive; the inhibitor tightly binds RNases in a 1:1 ratio. Supplied in one tube containing 10,000 U (40 U/ µL). The enzyme has been shown to inactivate RNases present in many tissues and cell types. Addition of the ribonuclease inhibitor (RI) has been shown to be useful whenever the integrity of RNA must be maintained such as in the preparation of cDNA by reverse transcription, in vitro RNA transcription, and in in vitro protein synthesis. RI does not inhibit RNase I, T1, T2, H, U1, U2, or CL3. RI requires a minimum of 1 mM DTT to maintain activity, and has an activity range between pH 5.0 to 8.0 with maximal activity between pH 7.0 and 8.0. Since the mode of inhibition is the formation of a 1:1 complex with RNases, care must be taken to avoid denaturation or oxidation of the ribonuclease inhibitor (e.g. by addition of SDS, urea, etc.). RI should be added to transcription, translation, and cDNA synthesis reactions to give a final concentration of 1 U/ µL. RNase Inhibitor is rigorously tested for contaminating RNase, exonuclease, endonuclease, and protease activity.

Unit Definition:
One unit is the amount of protein required to inhibit the activity of 5 ng of RNase A by 50%. Unit assay conditions: 100 mM Tris-acetate (pH 6.5), 1 mM EDTA, 1 mM cyclic 2',3'-CMP, and RNase inhibitor. Addition of RNase A initiates the reaction. RNase Inhibitor activity is measured by the inhibition of hydrolysis of cyclic 2', 3'-CMP by RNase A.

SUPERase• In™ RNase Inhibitor (20 U/μL) (Invitrogen™)

SUPERase• In™ RNase Inhibitor is a protein-based inhibitor of nonhuman origin that noncovalently binds and inhibits the most common and troublesome RNases, including RNase A, B, C, 1, and T1. Features of SUPERase• In™ RNase Inhibitor:

• Completely removes RNase contamination from glass and plastic surfaces
• Excels at removing high levels of RNase contamination where similar products fail
• Proven effective at removing high concentrations of dried-on RNase A
• Ideal for cleaning work surfaces, pipettors, and equipment that must be RNase-free

SUPERase• In™ RNase Inhibitor can be used in any application where RNase contamination could be problematic. Because it inhibits a broader range of RNases than traditional RNase inhibitors, SUPERase• In™ is the most effective RNase inhibitor available, providing a higher level of protection against degradation.

SUPERase• In™ does not interfere with other enzymes such as RNA polymerases, reverse transcriptase, or Taq DNA polymerase. Additionally, SUPERase• In™ is active up to 65°C and over a pH range of 5.5 to 8.5.

If you are plannning to use this product with standard antibody purification methods, please contact our technical support to discuss experimental design.

Unit definition
SUPERase• In™ RNase Inhibitor at 1 U/µL will block the degradation of 0.1 µg/µL labeled RNA by 2.5 pg/µL of RNase A, 2.5 pg/µL of RNase I, and 0.0075 U/µL of RNase T1, for 4 hours at 37°C, in 20 mM Tris-HCl, pH 7.5, 50 mM NaCl, 1 mM EDTA. Analysis is by denaturing PAGE. SUPERase
• In is currently the only ribonuclease inhibitor for which the unit activity is defined by such a functional assay.

RNaseOUT™ Recombinant Ribonuclease Inhibitor (Invitrogen™)

RNaseOUT™ Recombinant Ribonuclease Inhibitor is a potent noncompetitive inhibitor of pancreatic-type ribonucleases such as RNase A, and is used to avoid RNA degradation in a variety of applications. RNaseOUT™ Recombinant Ribonuclease Inhibitor is an acidic protein with a molecular weight of ~52 kDa. RNaseOUT™ inhibits RNase A, RNase B, and RNase C.

cDNA synthesis, RT-PCR, and in vitro transcription and translation

Purified by affinity chromatography from E. coli expressing a cloned porcine gene

Performance and quality testing
SDS-PAGE purity, endodeoxyribonuclease assay, protein concentration, specific activity, performance evaluated by RT-PCR

Unit definition
One unit inhibits 5 ng of RNase A by 50% using cytidine 2´, 3´ cyclic monophosphate (cCMP) as the substrate

Unit reaction conditions
100 mM Tris-acetate (pH 6.5), 1 mM EDTA, 0.2 mM cCMP, 2 µg RNase A in 1 mL from 0 to 10 min at 25°C

RNase Inhibitor (Applied Biosystems™)

RNase Inhibitor (ribonuclease inhibitor) is a 50 kDa recombinant enzyme used to inhibit RNase activity. It does not contain DNase or endonuclease activity. Features of this enzyme:

• Inhibits RNase activity—preventing degradation of RNA template
• Lacks DNA endonuclease activity—for better product yield

RiboLock RNase Inhibitor (40 U/µL) (Thermo Scientific™)

Thermo Scientific RiboLock RNase Inhibitor inhibits the activity of RNases A,B and C by binding them in a noncompetitive mode at a 1:1 ratio. It does not inhibit eukaryotic RNases T1, T2, U1, U2, CL3 as well as prokaryotic RNases I and H.


Performs under a wide range of reaction conditions
Protects RNA from degradation at temperatures up to 55°C


DTT provided in the Storage Buffer ensures stability during long term storage, but is not necessary for inhibitor activity. Recommended concentration 1 U/ µL of a reaction mixture.