Native horse heart cytochrome c (cytc) displays a very low reactivity toward ligands and does not exhibit catalytic properties. However, upon bovine cardiolipin (CL) binding, cytc achieves myoglobin-like properties. Here, NO binding to CL-cytc(III) between pH 7.2 and 9.5, at 20 °C, is reported. At pH 7.2, CL-cytc(III) undergoes reversible nitrosylation, whereas between pH 7.9 and 9.5 CL-cytc(III) undergoes irreversible reductive nitrosylation leading to the formation of CL-cytc(II)-NO. Over the whole pH range explored, first-order kinetics of NO binding to CL-cytc(III) (k = 9.3 s(-1) ) indicates that ligand binding is limited by the cleavage of the weak heme-Fe distal bond. Between pH 7.9 and 9.5, nitrosylated CL-cytc(III) converts to the ligand-free ferrous derivative (CL-cytc(II)), this process being pH-dependent (hOH-  = 3.0 × 10(3) M(-1) s(-1) ). Then, CL-cytc(II) converts to nitrosylated CL-cytc(II), in the presence of NO excess. The value of the second-order rate constant for CL-cytc(II) nitrosylation is essentially pH-independent, the average value of lon being 1.4 × 10(7) M(-1) s(-1) . These results agree with the view that CL-cytc nitrosylation may play a role in apoptosis regulation.

Ascenzi, P., Marino, M., Ciaccio, C., Santucci, R., Coletta, M. (2014). Reductive nitrosylation of the cardiolipin-ferric cytochrome c complex. IUBMB LIFE, 66, 438-447 [10.1002/iub.1283].

Reductive nitrosylation of the cardiolipin-ferric cytochrome c complex

CIACCIO, CHIARA;SANTUCCI, ROBERTO;COLETTA, MASSIMILIANO
2014-01-01

Abstract

Native horse heart cytochrome c (cytc) displays a very low reactivity toward ligands and does not exhibit catalytic properties. However, upon bovine cardiolipin (CL) binding, cytc achieves myoglobin-like properties. Here, NO binding to CL-cytc(III) between pH 7.2 and 9.5, at 20 °C, is reported. At pH 7.2, CL-cytc(III) undergoes reversible nitrosylation, whereas between pH 7.9 and 9.5 CL-cytc(III) undergoes irreversible reductive nitrosylation leading to the formation of CL-cytc(II)-NO. Over the whole pH range explored, first-order kinetics of NO binding to CL-cytc(III) (k = 9.3 s(-1) ) indicates that ligand binding is limited by the cleavage of the weak heme-Fe distal bond. Between pH 7.9 and 9.5, nitrosylated CL-cytc(III) converts to the ligand-free ferrous derivative (CL-cytc(II)), this process being pH-dependent (hOH-  = 3.0 × 10(3) M(-1) s(-1) ). Then, CL-cytc(II) converts to nitrosylated CL-cytc(II), in the presence of NO excess. The value of the second-order rate constant for CL-cytc(II) nitrosylation is essentially pH-independent, the average value of lon being 1.4 × 10(7) M(-1) s(-1) . These results agree with the view that CL-cytc nitrosylation may play a role in apoptosis regulation.
2014
Pubblicato
Rilevanza internazionale
Articolo
Esperti anonimi
Settore BIO/10 - BIOCHIMICA
English
Con Impact Factor ISI
Ascenzi, P., Marino, M., Ciaccio, C., Santucci, R., Coletta, M. (2014). Reductive nitrosylation of the cardiolipin-ferric cytochrome c complex. IUBMB LIFE, 66, 438-447 [10.1002/iub.1283].
Ascenzi, P; Marino, M; Ciaccio, C; Santucci, R; Coletta, M
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2108/89855
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