... b-ketothiolase; PaaZ, unknown, putative ring-cleavage enzyme, aldehyde dehydrogenase domain (N-terminus), MaoC-likeprotein domain (C-terminus). PaaX and PaaY may be involved in regulation. 3048 W. Ismail ... severalproteobacteria, including E. coli, Pseudomonas putida and Azoarcus evansii, contain clusters of 11–16 genes believed tobe involved in the catabolism of phenylacetate [2,5,6,9,10](Fig. 1). The paaK gene of ... the AA¢MM¢XX¢spin system using the chemical shifts and coupling constants summarized in Table 1.Fig. 7. Proposed outline of the pathway of aerobic metabolism of phenylacetate in E. coli. For...