loop_ _struct_biol_keywords.biol_id _struct_biol_keywords.text 1 'aspartyl-protease' 1 'aspartic-protease' 1 'acid-protease' 1 'aspartyl-proteinase' 1 'aspartic-proteinase' 1 'acid-proteinase' 1 'enzyme' 1 'protease' 1 'proteinase' 1 'dimer' 2 'drug-enzyme complex' 2 'inhibitor-enzyme complex' 2 'drug-protease complex' 2 'inhibitor-protease complex' 3 'drug-enzyme complex' 3 'inhibitor-enzyme complex' 3 'drug-protease complex' 3 'inhibitor-protease complex'