Effect of iron chelators on the zinc-containing enzyme phospholipase C.

Purified phospholipase C, 0.1 mg/mL in 60% sorbitol, was incubated for 30 minutes with either PBS (control), the iron chelators CP20 or DFO (300 μM IBE), the zinc chelator TPEN (50 μM), or CP20 and DFO (1 μM) in combination with TPEN (0.1 μM). Following this interval, NPPC (20 mM) was added and phospholipase C activity assessed by spectrophotometry over 1 hour at 410 nm. The data shown are the mean ± SD of 4 independent experiments performed in duplicate.