Presence of two forms of palmityl-CoA-ACP-transacylase in homogenates of Mycobacterium smegmatis, purification using the monomer-polymer interconvertibility.

Homogenates of Mycobacterium smegmatis have been shown to contain, among other acyl-transfer enzymes, two entities endowed with palmityl-CoA-ACP-transacylase activity (1973, this journal, 55, 1381-1394). The present report demonstrates that these two entities, now called palmityl-CoA-ACP-transacylase I and palmityl-CoA-ACP-transacylase II, following their elution rate from a Sephadex G-150 column, are two interconvertible forms of the same enzyme. Form II, apparently predominant in the crude homogenates, is converted, during the purification steps, into Form I. The latter is convertible into Form II. It is observed that when the concentration of the enzyme increases, Form I becomes predominant. A purification of 800-fold was achieved, particularly by taking advantage of this convertibility properties. Parallel experiments conducted on S. cerevisiae and E. coli homogenates show the presence of the enzyme in the former and its absence in the latter microorganism.