Phosphatidylinositol-specific phospholipase C from Bacillus cereus: improved purification, amino acid composition, and amino-terminal sequence

Phosphatidylinositol-specific phospholipase C was purified in a 27% yield from the culture medium of Bacillus cereus by a combination of ammonium sulfate precipitation and ion-exchange and hydrophobic interaction chromatography. The purified enzyme was free of other phospholipase C-type activities and exhibited a high specific activity of approximately 1,300 units/mg. Amino acid composition analysis and sodium dodecyl sulfate-polyacrylamide gel electrophoresis indicated a molecular weight of about 35 kDa. The sequence of the first 29 N-terminal amino acids was also determined.