Ribonuclease H (RNase H) is an endoribonuclease that specifically degrades the RNA strand in RNA-DNA hybrids, generating 5´-phosphate-terminated oligoribonucleotides and single-stranded DNA.

Applications
Removal of mRNA during second-strand cDNA synthesis. Removal of poly(A) sequences from mRNA in the presence of Oligo(dT). Oligodeoxynucleotide-mediated RNA cleavage.

Source
Fermented and purified from recombinant Escherichia coli.

Performance and Quality Control
Tested for ribonuclease, non-specific deoxyribonuclease, 3´ and 5´ deoxyriboexonuclease activities.

Unit Definition
One unit is defined as the amount of enzyme that hydrolyzes 1 nmol of RNA in ³H-labeled poly(A)·poly(dT) into acid-soluble material within 20 min at 37°C.

Unit Assay Conditions
20 mM Tris-HCl (pH 7.5), 0.1 M KCl, 10 mM MgCl₂, 0.1 mM DTT, 5% (w/v) sucrose, 0.5 nmol ³H-labeled poly(A)·poly(dT) and 50 µL enzyme, incubated at 37°C for 20 min.