3.1.30.1 endonucleolytic cleavage to 5'-phosphomononucleotide and 5'-phosphooligonucleotide end-products - - 3.1.30.1 endonucleolytic cleavage to 5'-phosphomononucleotide and 5'-phosphooligonucleotide end-products endonuclease I catalyzes the breakage of the P-O3' bond 664133