The pH dependence of the activity of Cu,Zn superoxide dismutases from bovine erythrocytes and shark liver was studied by pulse radiolysis in both the native enzymes and those chemically modified at lysine side chains. The study was aimed at identifying the residues responsible for the activity decrease at pH > 9, observed in all native Cu,Zn superoxide dismutases, and is based on the Lys --> Arg substitution present in the shark protein at position 134, which has been established to be critical for the catalytic efficiency of the enzyme. Both native enzymes display a pH dependence that can be deconvoluted by three deprotonation equilibria, at pH 9-9.5 (pK(1)), at pH 10.2 (pK(2)), and at pH 11.5 (pR(3)). pK(1) is lacking in both the modified enzymes and thus can be assigned to activity-linked lysine residues. pK(2) is clearly dominated by Arg134 in the modified shark enzyme and can be assigned to surface arginine residues. pK(3) is shared by all four enzyme forms and is likely to be due to the invariant Arg141. (C) 1995 Academic Press, Inc.

Polticelli, F., Oneill, P., Costanzo, S., Lania, A., Rotilio, G., Desideri, A. (1995). IDENTIFICATION OF THE RESIDUES RESPONSIBLE FOR THE ALKALINE INHIBITION OF THE ACTIVITY OF CU,ZN SUPEROXIDE-DISMUTASE - A STUDY OF NATIVE AND CHEMICALLY-MODIFIED ENZYMES RID A-4573-2009. ARCHIVES OF BIOCHEMISTRY AND BIOPHYSICS, 321(1), 123-126 [10.1006/abbi.1995.1376 WC Biochemistry & Molecular Biology; Biophysics].

IDENTIFICATION OF THE RESIDUES RESPONSIBLE FOR THE ALKALINE INHIBITION OF THE ACTIVITY OF CU,ZN SUPEROXIDE-DISMUTASE - A STUDY OF NATIVE AND CHEMICALLY-MODIFIED ENZYMES RID A-4573-2009

POLTICELLI, Fabio;
1995-01-01

Abstract

The pH dependence of the activity of Cu,Zn superoxide dismutases from bovine erythrocytes and shark liver was studied by pulse radiolysis in both the native enzymes and those chemically modified at lysine side chains. The study was aimed at identifying the residues responsible for the activity decrease at pH > 9, observed in all native Cu,Zn superoxide dismutases, and is based on the Lys --> Arg substitution present in the shark protein at position 134, which has been established to be critical for the catalytic efficiency of the enzyme. Both native enzymes display a pH dependence that can be deconvoluted by three deprotonation equilibria, at pH 9-9.5 (pK(1)), at pH 10.2 (pK(2)), and at pH 11.5 (pR(3)). pK(1) is lacking in both the modified enzymes and thus can be assigned to activity-linked lysine residues. pK(2) is clearly dominated by Arg134 in the modified shark enzyme and can be assigned to surface arginine residues. pK(3) is shared by all four enzyme forms and is likely to be due to the invariant Arg141. (C) 1995 Academic Press, Inc.
1995
Polticelli, F., Oneill, P., Costanzo, S., Lania, A., Rotilio, G., Desideri, A. (1995). IDENTIFICATION OF THE RESIDUES RESPONSIBLE FOR THE ALKALINE INHIBITION OF THE ACTIVITY OF CU,ZN SUPEROXIDE-DISMUTASE - A STUDY OF NATIVE AND CHEMICALLY-MODIFIED ENZYMES RID A-4573-2009. ARCHIVES OF BIOCHEMISTRY AND BIOPHYSICS, 321(1), 123-126 [10.1006/abbi.1995.1376 WC Biochemistry & Molecular Biology; Biophysics].
File in questo prodotto:
Non ci sono file associati a questo prodotto.

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11590/124655
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 11
  • ???jsp.display-item.citation.isi??? 11
social impact