Phosphatidylinositol specific isoenzymes of phospholipase D from Catharanthus roseus. Purification and characterization

摘要: Abstract Microsomal membranes from suspension cultured Catharanthus roseus cells were found to contain phospholipase D activity (EC 3.1.4.4) towards phosphatidylinositol (PI). After extraction with buffer containing Triton X-100, two isoenzymes apparent molecular weights of 50 000 and 125 partially purified. The enzymes accepted only PI as substrate transphosphatidylation could not be detected. Whereas several phospholipids slightly inhibitory, phosphatidyl glycerol had stimulatory properties. required divalent cations for activity, Ca 2+ Mg equally effective. In the presence deoxycholate , K m values in range 20–40 μM. Although smaller protein a higher temperature stability lower p I value, both revealed equal enzymic This is first report on plant PI-specific D.