passages.id: split_8_test_3124_passage
passages.type: progene_text
passages.text: Transcription of three hitherto - identified copper - responsive genes , copA ( copper efflux transporter ) , cueO ( multicopper oxidase ) and cusC ( tripartite copper pump component ) became maximum at 5 min after addition of copper sulphate , and thereafter decreased to the preshift levels within 30 min .