Phospholipid degradation by native phospholipase C from Bacillus cereus and enzyme forms where one or both of the Zn2+ prosthetic groups had been replaced with Co2+ was studied in human erythrocyte membranes (ghosts) and resuspended freeze-dried bovine brain myelin. The rate of total phospholipid degradation was 2-9-fold more rapid with erythrocytes than with myelin. With both membrane systems the activity decreased in the order ZnZn-enzyme greater than ZnCo-enzyme greater than CoCo-enzyme. For all three enzyme forms with either membrane system, phosphatidylethanolamine (or the ethanolamine-containing phosphoglycerides) and phosphatidylcholine were hydrolysed most rapidly and sphingomyelin least. The relative rate of sphingomyelin degradation was highest with the ZnCo-enzyme. In myelin at low ionic strength there seemed to be a core of phospholipid that was very resistant to degradation by native phospholipase C but which was much more accessible to the Co2+-substituted forms. It is suggested that ZnCo-phospholipase C has potential applications in membrane studies.
Effect of Co2+-substitution on the substrate specificity of phospholipase C from Bacillus cereus during attack on two membrane systems
- Views Icon Views
- Share Icon Share
C Little, S E Aakre, M G Rumsby, K Gwarsha; Effect of Co2+-substitution on the substrate specificity of phospholipase C from Bacillus cereus during attack on two membrane systems. Biochem J 1 October 1982; 207 (1): 117–121. doi: https://doi.org/10.1042/bj2070117
Download citation file: