Ribonuclease T1 核糖核酸酶 T1

Source: Aspergillus oryzae

I.U.B: 3.1.27.3

Ribonuclease T1 is an endoribonuclease, highly specific for the cleavage of RNA or deaminated RNA between guanosine 3-phosphate residues (or inosine 3-phosphate) and the 5-OH residues of adjacent nucleotides with the formation of the corresponding intermediate 2, 3-cyclic phosphates. It cleaves single-stranded RNA releasing oligonucleotides from the guanosine 3-phosphate termini. The enzyme has a molecular weight of 11 kDa. The optimum pH is 7.5. RNase T1 is inhibited by Ag⁺, Zn²⁺, Cu²⁺, and Hg²⁺ at 1 X 10^-3 M. The stimulatory effects of both histidine and EDTA are attributed to chelation of contaminating inhibitor cations. The enzyme assay is essentially the method of Egami et al., Prog. in Nucleic Acid Res. and Molec. Biol., III, 59 (1964) based upon the release of acid soluble oligonucleotides following the digestion of yeast RNA.