Enzovera RNase A is a high-purity bovine pancreatic ribonuclease available in two formats: EV-NUC-007 (Lyophilized, ≥40 Kunitz Units/mg, 1 g and 10 g bottles) and EV-NUC-008 (Solution 10 mg/ml, ≥350 Kunitz Units/ml, 5 ml and 10 ml bottles). RNase A is the most widely used ribonuclease in molecular biology, valued for its exceptional stability, high specific activity against single-stranded RNA, and ability to degrade RNA rapidly and completely under standard laboratory conditions while leaving DNA fully intact.

Mechanism. RNase A (EC 3.1.27.5) is a small (13.7 kDa) endoribonuclease that cleaves single-stranded RNA specifically at the 3′ side of pyrimidine residues (cytidine and uridine), generating 2′,3′-cyclic phosphate intermediates subsequently hydrolyzed to 3′-nucleotide monophosphates. The active-site histidines His-12 and His-119 act as general acid and base catalysts in the transesterification mechanism, with Lys-41 stabilizing the transition state. RNase A is a highly cationic protein (pI ~9.6) that binds RNA electrostatically; it is active over pH 2–10, stable across a broad temperature range, and resistant to denaturation by urea, guanidinium, and moderate SDS concentrations. The enzyme is irreversibly inactivated by DEPC (which carbethoxylates the catalytic histidines) or by heating at 100°C.

Salt-dependent specificity. RNase A cleaves efficiently at both low ionic strength (≤50 mM NaCl) and high ionic strength (≥300 mM NaCl), but substrate selectivity differs. At low salt, the enzyme cleaves single-stranded RNA and can also act on the RNA strand of RNA:DNA hybrids. At high salt (≥300 mM NaCl), activity is restricted to single-stranded RNA — a property exploited in the RNase Protection Assay (RPA), where double-stranded RNA formed by probe-mRNA hybridization is specifically protected from degradation. EV-NUC-007 (lyophilized) is recommended for bulk applications including plasmid purification; EV-NUC-008 (solution) is preferred for high-throughput workflows where pipetting accuracy at small volumes is important.

Recommended applications:

• RNA removal during plasmid DNA miniprep and midiprep purification
• RNase Protection Assay (RPA) for quantitative gene expression analysis
• Removal of RNA contamination from genomic DNA preparations
• Elimination of RNA from protein preparations for crystallography and biochemical assays
• RNase mapping of RNA secondary structure and RNA:protein interaction sites
• Cell-free transcription and translation reaction cleanup
• Generation of nucleic-acid-free protein reference materials