Aspergillus oryzae Ribonuclease T2 is a member of the RNase T2 family of endonucleases that are present in a wide variety of microbial, plant and animal species. In contrast to Aspergillus oryzaeRibonuclease T1, which is an exclusively guanylic-acid specific endonuclease, all RNase T2-like enzymes are essentially base non-specific. However, RNase T2 endonucleases from different species can show slight base preferences. The fungal enzymes, including?Aspargillus oryzae RNaseT2, show slight base preference in the following order: A>G>C, U. RNase T2 cleaves between the 3’-phosphate residue of one base and the 5’-OH residue of the adjacent nucleotide forming a 2’, 3’-cyclic phosphate intermediate followed by the generation of oligonucleotides with 3’-phosphate residues. RNase T2 has a molecular weight of 36 kDa and 12-15% of its mass is composed of carbohydrate. It has an isoelectric point of 5.0 and optimum activity at pH 4.5. RNase T2 is strongly inhibited by Cu2+, Zn2+ and Hg2+ and to a lesser degree by Ca2+, Mg2+and heparin. Mononucleotides and RNase T2 digestion products can also act as competitive inhibitors. EDTA will stimulate activity, especially in the presence of divalent cations.

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