MALONATE DECARBOXYLASE OF PSEUDOMONAS-PUTIDA IS COMPOSED OF 5 SUBUNITS

Two different forms of malonate decarboxylase were purified from Pseud omonas putida. The active form was composed of the five different subu nits alpha (60 kDa), beta (33 kDa), gamma (28 kDa), delta (13 kDa), an d epsilon (30 kDa) and the inactive form was composed of the four subu nits lacking the epsilon subunit. The former catalyzed the decarboxyla tion of malonate to acetate, but the latter could not, although it ret ained both activities of acetyl-CoA:malonate CoA transferase and malon yl-CoA decarboxylase. The delta subunit of the active form was acylate d by the incubation with [2-C-14]malonyl-CoA, but the delta subunit of the inactive form was not labeled. From the above results and the N-t erminal amino acid sequence analysis, it was concluded that the epsilo n subunit was an essential subunit to function as malonyl-CoA:ACP tran sacylase, which was an indispensable component of the enzyme for the c yclic decarboxylation of malonate. (C) 1998 Federation of European Mic robiological Societies. Published by Elsevier Science B.V. All rights reserved.