DIPEPTIDYL AMINOPEPTIDASE-IV FROM PSEUDOMONAS SP WO24

Dipeptidyl aminopeptidase IV from Pseudomonas sp. WO24 was purified as two molecular forms of 84 and 82-kDa by SDS-PAGE, Peptide mapping and N-terminal sequence analyses indicated that both proteins might be de rived from the same protein, and that the 82-kDa molecule might be a t runcated form from the 84-kDa molecule at least at the N-terminus. The DAP TV gene of Pseudomonas sp, WO24 was cloned and expressed in E, co li, The enzyme expressed in E, coli JM109 harboring a hybrid plasmid, pYO-6A. with about a 3-kbp fragment containing the DAP IV gene, was pu rified with an activity recovery of 24%. The recombinant enzyme also h ad the same two molecular forms, though the ratio of the to forms (abo ut 1:1) was different from that of the native ones (about 1:4), The na tive and recombinant enzyme preparations had similar specific activiti es, suggesting that the 84 and 82-kDa molecules are in an active form and have almost the same specific activity, The molecular mass, the su bunit number, the substrate specificity, and the effects of various in hibitors of the native enzyme indicated that this enzyme was a typical DAP IV and had properties similar to those of Flavobacterium meningos epticum rather than others.