DIENELACTONE HYDROLASE FROM PSEUDOMONAS-CEPACIA

Dienelactone hydrolases have previously been shown to play a crucial r ole in chlorocatechol degradation via the modified ortho cleavage path way. Recently, the enzymes induced in 4-fluorobenzoate-utilizing bacte ria have been classified into three groups on the basis of their speci ficity towards cis- and trans-dienelactone. The dienelactone hydrolase and the 3-oxoadipate enol-lactone hydrolase from Pseudomonas cepacia have now been purified to apparent homogeneity and characterized with respect to molecular mass and amino acid composition. The dienelactone hydrolase has a distinct preference for cis-dienelactone and did not convert the trans isomer or muconolactone, 3-oxoadipate enol-lactone, or 4-fluoromuconolactone to a significant extent. In properties like a mino acid composition, pH optimum of activity, and lack of inhibition by p-chloromercuribenzoate, the P. cepacia dienelactone hydrolase diff ered substantially from 3-oxoadipate enol-lactone hydrolases and other dienelactone hydrolases.