Table 1.

Effect of mannitol, p-HPA and bicarbonate on peroxynitrite-dependent CBS inactivation

Condition a	CBS activity (U/mg)
CBS	561 ± 35 b
+ Peroxynitrite	105 ± 1
+ Peroxynitrite + mannitol	67 ± 5
+ Mannitol	611 ± 47
+ Peroxynitrite + p-HPA	269 ± 11
+ p-HPA	521 ± 5
+ Peroxynitrite + NaHCO3	48 ± 3
+ NaHCO3	536 ± 29

^aCBS (5 μM) was exposed to peroxynitrite (400 μM) in the presence and absence of mannitol (100 μM), p-HPA (91 μM) and NaHCO₃ (25 mM) in phosphate buffer (0.1 M, pH 7.4, DTPA 0.1 mM). After 2 min at 37 °C the enzymatic activity was determined by the ninhydrin method.

^bData are the mean ± standard deviation of triplicates.