Characterization of multiple forms of phosphoinositide-specific phospholipase C from bovine aorta.
Three forms (I, II and III) of phospholipase C were separated from the cytosol of bovine aorta by chromatography on Blue Sepharose. All three forms showed an increase of enzyme activity when free Ca2+ in the assay was raised between 40 microM and 9 mM. The pH optimum was in the range of 6.0 to 6.5 for each subtype. Marked differences in thermostability were found when the three enzyme forms were pre-incubated at 50 degrees C prior to the assay. All three forms were able to hydrolyse phosphatidylinositol as well as phosphatidylinositol 4-phosphate and phosphatidylinositol 4,5-bisphosphate. In contrast, when phosphatidylcholine was used as substrate, no enzyme activity was observed. Spermine and spermidine, but not putrescine, were able to stimulate form I and III; neomycin sulphate inhibited all three subtypes.
Späth
M
M
Physiologisches Institut Universität Freiburg, Germany.
Woscholski
R
R
Schächtele
C
C
D000818:Animals; D001011:Aorta / Q000201:enzymology*; D002118:Calcium / Q000378:metabolism; D002417:Cattle; D002846:Chromatography, Affinity; D004795:Enzyme Stability; D006863:Hydrogen-Ion Concentration; D010716:Phosphatidylinositols / Q000378:metabolism*; D010743:Phospholipids / Q000378:metabolism; D013379:Substrate Specificity; D013696:Temperature; D010738:Type C Phospholipases / Q000037:antagonists & inhibitors / Q000378:metabolism*
D010716:Phosphatidylinositols; D010743:Phospholipids; D010738:Type C Phospholipases; D002118:Calcium