Purification and properties of two phospholipases D from Streptomyces sp

Two enzymes with phospholipase D activity were purified from Streptomyces strains (PMF and PM43) by column chromatography on Fractogel TSK CM-650(S), Sephadex G-100 and Fractogel EMD DEAE-650(M). The purified preparations were found to be homogeneous by SDS-PAGE, capillary electrophoresis and analytical gel filtration. The molecular masses, assessed by MALDI-MS spectrometry, were 53.864 kDa for PMF and 54.147 kDa for PM43. The isoelectric point was 9.1 for both enzymes. The enzymes were most active at around 60 degrees C and stable between pH 4 and 9 and below 50 degrees C. The pH optima were between 4 and 6 for PMF and between 6 and 7 for PM43. Both phospholipases displayed high transphosphatidylation activity but PMF was more selective than PM43.