The copper,zinc-containing superoxide dismutase electromorphs from chicken erythrocytes have been isolated, their complete amino acid sequence determined and the identity of the protein moieties established. All electromorphs are constituted by a polypeptide chain made of 153 amino acid residues, corresponding to a molecular mass of 15598 Da. Accurate molecular mass determination by electrospray mass spectrometry of the separated electromorphs unequivocally proved that, in the chicken superoxide dismutase, either one or two cysteine residues/subunit are involved in a mixed disulfide with glutathione. The same post-translational modification has been proven to occur in human superoxide dismutase. A different rate of S-thiolation by endogenous glutathione was also demonstrated to be responsible for charge heterogeneity in cells. Effect of this modification on the catalytic and molecular properties of superoxide dismutases, and possible mechanisms for the S-thiolation process, were also investigated and discussed.
Amino acid sequence of chicken Cu, Zn-containing superoxide dismutase and identification of glutathionyl adducts at exposed cysteine residues / Schinina', Maria Eugenia; Patrizia, Carlini; Fabio, Polticelli; Francesca, Zappacosta; Bossa, Francesco; Calabrese, Lilia. - In: EUROPEAN JOURNAL OF BIOCHEMISTRY. - ISSN 0014-2956. - 237:2(1996), pp. 433-439. [10.1111/j.1432-1033.1996.0433k.x]
Amino acid sequence of chicken Cu, Zn-containing superoxide dismutase and identification of glutathionyl adducts at exposed cysteine residues
SCHININA', Maria Eugenia;BOSSA, Francesco;CALABRESE, Lilia
1996
Abstract
The copper,zinc-containing superoxide dismutase electromorphs from chicken erythrocytes have been isolated, their complete amino acid sequence determined and the identity of the protein moieties established. All electromorphs are constituted by a polypeptide chain made of 153 amino acid residues, corresponding to a molecular mass of 15598 Da. Accurate molecular mass determination by electrospray mass spectrometry of the separated electromorphs unequivocally proved that, in the chicken superoxide dismutase, either one or two cysteine residues/subunit are involved in a mixed disulfide with glutathione. The same post-translational modification has been proven to occur in human superoxide dismutase. A different rate of S-thiolation by endogenous glutathione was also demonstrated to be responsible for charge heterogeneity in cells. Effect of this modification on the catalytic and molecular properties of superoxide dismutases, and possible mechanisms for the S-thiolation process, were also investigated and discussed.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.