American Society of Hematology

Fig. 6.

$Fig. 6. Ceramide, DAG, and acidic pH, Mg2+-independent and neutral pH, Mg2+-dependent sphingomyelinase (ASMase and NSMase, respectively) activity in purified populations of Molt-4 cells treated with GW1843. Log-phase Molt-4 cells were treated with 8 nmol/L GW1843 for 24 hours, cell fractions were resolved on histopaque step gradients, and assayed for ASMase activity (open), NSMase activity (closed), ceramide levels (cross-hatched), and DAG (shaded) as described in Materials and Methods. Control activity of NSMase (mean ± SEM) was 3.3 ± 0.48 pmol/h/106 cells, control activity of ASMase was 3.1 ± 0.18 pmol/h/106cells and control levels of ceramide and DAG were 4.0 ± 1.8 and 29.2 ± 7.0 pmol/nmol lipid phosphate, respectively. The graph represents the average of four separate experiments (mean ± SEM).$

Ceramide, DAG, and acidic pH, Mg²⁺-independent and neutral pH, Mg²⁺-dependent sphingomyelinase (ASMase and NSMase, respectively) activity in purified populations of Molt-4 cells treated with GW1843. Log-phase Molt-4 cells were treated with 8 nmol/L GW1843 for 24 hours, cell fractions were resolved on histopaque step gradients, and assayed for ASMase activity (open), NSMase activity (closed), ceramide levels (cross-hatched), and DAG (shaded) as described in Materials and Methods. Control activity of NSMase (mean ± SEM) was 3.3 ± 0.48 pmol/h/10⁶ cells, control activity of ASMase was 3.1 ± 0.18 pmol/h/10⁶cells and control levels of ceramide and DAG were 4.0 ± 1.8 and 29.2 ± 7.0 pmol/nmol lipid phosphate, respectively. The graph represents the average of four separate experiments (mean ± SEM).

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