Table 1.

Rate constants of some relevant reactions involved in peroxynitrite biochemistry and tyrosine nitration

Reaction	k (M−1 s−1)	Reference
•NO + O2•− → ONOO−	0.4–1.6 × 1010	30–32
ONOO− + CO2 → ONOOCO2−	5.8 × 104	16,33
ONOOH + Prx5(-S−) → NO2− + Prx5(-SOH)	7 × 107	34
ONOOH + GS− → NO2− + GSOH	1.4 × 103	35
ONOOH + MPO(Fe3+) → •NO2 + MPO(Fe4+ = O)	6.2 × 106	36
ONOOH + Hb(Fe2+)O2 → Hb(Fe3+) + O2•− + NO3− + H+	1.04 × 104	37
ONOO− + Mn3+TE-2-PyP → •NO2 + O = Mn4+TE-2-PyP	3.4 × 107	38
MPO(P•π+Fe4+ = O) + NO2− → MPO(PFe4+ = O) + •NO2	2.0 × 106	39
•OH + NO2− → •NO2 + OH−	6.0 × 109	40
Tyr + CO3•− → Tyr• + HCO3−	4.5 × 107	41
Tyr + •OH → Tyr(OH)•	1.2 × 1010	42
Tyr + •NO2 → Tyr• + NO2− + H+	3.2 × 105	43
Tyr + MPO(Fe4+ = O) → Tyr• + MPO(Fe3+) + OH−	1.6 × 104	44
Tyr + LOO• → Tyr• + LOOH	4.8 × 103	25
Tyr + LO• → Tyr• + LOH	3.5 × 105	26
Tyr• + •NO2 → NO2Tyr	3.0 × 109	43
Tyr• + Tyr• → DiTyr	2.3 × 108	45

Experimental conditions used for rate constant determination (e.g. temperature, pH) can be found in each specific reference.

The homolysis of ONOOH to yield ^•OH and ^•NO₂ in a first order process is described in the text and shown in Fig. 1. The reactions of peroxynitrite with peroxiredoxins, glutathione and oxyhemoglobin inhibit tyrosine nitration by reduction or isomerization of peroxynitrite.

Prx5, peroxiredoxin 5; GS⁻, glutathione; MPO, myeloperoxidase; HbO₂, oxyhemoglobin; Mn³⁺TE-2-PyP, manganese (III) meso-tetrakis ((N-ethyl)pyridinium-2-yl) porphyrin; MPO(P^•π+Fe⁴⁺ = O), myeloperoxidase compound I.