PURIFICATION AND SOME PROPERTIES OF LIGNOSTILBENE-ALPHA,BETA-DIOXYGENASE ISOZYME-IV FROM PSEUDOMONAS-PAUCIMOBILIS TMY1009

Lignostilbene-alpha,beta-dioxygenase isozyme IV was purified from ultr asonic extracts of Pseudomonas paucimobilis TMY1009 through four steps of column chromatography. The fraction obtained gave a single band on SDS-PAGE and a single peak on reversed-phase HPLC and DEAE-HPLC> The specific activity and K-m of purified isozyme IV were 110 mu kat/g and 4.2 mu M for 4,4'-dihydroxy-3,3'-dimethoxystilbene, 150 mu kat/g and 3.3 mu M for 4,2'-dihydroxy-3,3-dimethoxy-5-(2 ''-carboxyvinyl)stilben e. The molecular mass of intact isozyme IV was estimated to be 94 kDA by SDS-PAGE under denaturing conditions. The N-terminal amino acid seq uence of isozyme IV differed slightly from that of other isozymes. Iso zyme IV seemed to be composed of two identical subunits, gamma gamma.