Table 1.

Effects of bicarbonate and PNU-101033 on ONOO⁻-induced modifications of TH

Treatment	TH activity (% control)	Sulfhydryl content (# per monomer)	Tyrosine nitration (# per monomer)
Control	100	6.8  ± 0.2	0
ONOO− (0.5 mm)	13.2  ± 4	1.2  ± 0.4	2.4  ± 0.1
+ Bicarbonate (10 mm)	41.2  ± 6*	3.9  ± 0.5*	4.2  ± 0.5*
+ PNU-101033 (100 μm)	31.1  ± 1*	2.5  ± 0.5*	0*

TH was treated with ONOO⁻ (0.5 mm) as described with or without the indicated concentrations of either bicarbonate or PNU-101033. After treatment, residual TH activity was assayed, and remaining enzyme was analyzed for sulfhydryl and nitrotyrosine content (separate samples). Results represent mean ± SEM for three to five independent experiments performed in duplicate. The effects of bicarbonate and PNU-101033 on TH were significantly different from those of ONOO⁻ alone (p < 0.05; Student's t test) where indicated (*).