Purification and characterization of the 2nd 5'-nucleotide-forming nuclease from Lentinus edodes

The 2nd endonuclease (nuclease Le3) which hydrolyzes both RNA and heat denatured DNA to 5'-nucleotides was purified from the fruit bodies of Lentinus edodes to a homogeneous state by SDS PAGE. The nuclease was different from the nuclease Le1 previously characterized [H. Shimada et al. Chem. Pharm. Bull., 39, 2633-2637 (1991)] in molecular weight, optimal pH and N-terminal amino acid sequence. The N-terminal amino acid sequence of nuclease Le3 analyzed up to the 20th residue showed that 50% of the amino acid residues are identical to nuclease Le1.