of p putida ppg2 pjrs48 the level of e1 sequence id no 2 and sequence id no 3 activity was surprisingly high compared to extracts of p putida ppg2 grown in valine sioleucine medium table 3 thus expression of bkda1 sequence id no 2 and bkda2 sequence id no 3 from p putida js113 pjrs50 was nearly 40 times that obtained in p putida ppg2 which seems to be much higher than could be accounted for by copy number alone when p putida js113 pjrs50 was grown in valine isoleucine medium the specific activity was about twice that obtained in l broth these results also suggest that the bkd operon sequence id no 1 is negatively regulated probably by a small amount of endogeneous repressor which is titrated by the multiple copies of pjrs50 in the cell again p putida js113 pjrs49 did not grow in this medium suggesting that bkda1 sequence id no 2 and bkda2 sequence id no 3 were not expressed bkda1 sequence id no 2 and bkda2 sequence id no 3 expression was repressed by glucose table 3 it is pertinent to note that pseudomonads do not contain appreciable amounts of camp bacterial strains and plasmids the p putida strains and plasmids used in this study are listed in table 4 branched chain keto acid dehydrogenase mutants listed in table 4 cannot grow on the valine isoleucine agar described.