RNA endonuclease activity phosphorus-oxygen lyase activity rRNA endonuclease activity https://github.com/geneontology/go-ontology/issues/24408 https://github.com/geneontology/go-ontology/issues/30193 Catalysis of the reaction: a 28S rRNA containing guanosine-adenosine pair + H2O = an [RNA fragment]-3'-adenosine-3'-phosphate + a 5'-a hydroxy-guanosine-3'-[RNA fragment]. MetaCyc:3.1.27.10-RXN alpha-sarcin molecular_function GO:0033902 EC:4.6.1.23