Lipase Activity of Mycoplasma

Abstract

All of eight Mycoplasma strains tested were capable of hydrolyzing tributyrin. The saprophytic M. laidlawii strains showed the lowest lipolytic activity, and the parasitic M. gallisepticum the highest. The properties of M. gallisepticum lipase were studied in some detail. The lipolytic activity of this organism was highest at the logarithmic phase of growth and declined steeply afterwards. The enzyme was not bound to the cell membrane and appeared in the soluble fraction of disrupted cells. The cell extract hydrolyzed tributyrin much faster than trilaurin or triolein. Methyl-oleate and "Tween-80" were only slowly hydrolyzed. Cholesteryl-acetate and stearate were not hydrolyzed by cell extract or by intact M. gallisepticum cells. Partial purification of the lipase was accomplished by ammonium-sulfhate fractionation of cell-extract proteins, followed by anion-exchange chromatography. The partially purified enzyme did not require inorganic ions for activity and its optimal pH value varied between 7.5 and 8.0, depending on the substrate tested.