obsolete regulation of isomerase activity https://github.com/geneontology/go-ontology/issues/22455 true GO:0010911 This term was obsoleted because it represents a molecular function. OBSOLETE. Any process that modulates the activity of an isomerase. An isomerase catalyzes the geometric or structural changes within one molecule. Isomerase is the systematic name for any enzyme of EC class 5. biological_process