passages.id: split_8_test_2772_passage
passages.type: progene_text
passages.text: Superimposed in the specific MhpR - mediated regulation of the Pa promoter , we have observed a strict catabolite repression control carried out by the cAMP receptor protein ( CRP ) that allows expression of the mhp catabolic genes when the preferred carbon source ( glucose ) is not available and 3HPP is present in the medium .