_EC 3.1.31.- Endoribonucleases active with either ribo- or deoxyribonucleic ac 332 PDB entries  
EC 3.-.-.- Hydrolases. [51,972 PDB entries]
EC 3.1.-.- Acting on ester bonds. [12,883 PDB entries]
EC 3.1.31.- Endoribonucleases active with either ribo- or deoxyribonucleic ac [332 PDB entries]
EC 3.1.31.1 micrococcal nuclease. [332 PDB entries]