Fast-reacting thiols in rat hemoglobin can intercept damaging species in erythrocytes more efficiently than glutathione
- Rossi, R
- Barra, Donatella
- Bellelli, Andrea
- Boumis, Giovanna
- Canofeni, S
- DI SIMPLICIO, P
- Lusini, L
- Pascarella, Stefano
- Amiconi, Gino
DOIAbstract
The S-conjugation rates of the free-reacting thiols present on each component of rat hemoglobin with 5,5-dithio-bis(2,2-nitrobenzoic acid) (DTNB) have been studied under a variety of conditions. On the basis of their reactivity with DTNB (0.5 mM), three classes of thiols have been defined as follows: fast reacting (fHbSH), with t1/2 <100 ms; slow reacting (sHbSH), with t1/2 30-50 s; and very slow reacting (vsHbSH), with t1/2 180-270 s. Under paraphysiological conditions, fHbSH (identified with Cys-125beta(H3)) conjugates with DTNB 100 times faster than glutathione and approximately 4000 times more rapidly than (v)sHbSH (Cys-13alpha(A11) and Cys-93beta(F9)). Such characteristics of fHbSH reactivity that are independent of the quaternary stat...
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