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Oxidative DNA damage and level of thiols as related to polymorphisms of MTHFR, MTR, MTHFD1 in Alzheimer's and Parkinson's diseases

100%

Dorszewska J. , Florczak J. , Rozycka A. , Kempisty B. , Jaroszewska-Kolecka J. , Chojnacka K. , Trzeciak W. H. , Kozubski W.

2007

tom 67

nr 2

113-129

Neurodegenerative diseases, such as Alzheimer's disease (AD) and Parkinson's disease (PD), are accompanied by increased levels of 8-oxo-2'-deoxyguanosine (8-oxo2dG) and alterations in levels of homocysteine (Hcy), methionine (Met), and cysteine (Cys). Hcy may undergo remethylation due to involvement of MTHFR, MTR and MTHFD1 proteins. Present studies are aimed at determination of 8-oxo2dG, Hcy, Met, and Cys in AD and PD patients as well as in control groups, using HPLC/EC/UV, as well as estimation, by restriction analysis, frequency of following gene polymorphisms: MTHFR (C677T, A1298C, G1793A), MTHFD1 (G1958A), and MTR (A2756G). In AD there were significant differences of the levels of only Cys (GG, MTHFR, G1793A) and Met/Hcy (AA, MTHFD1, G1958A) whereas in PD there were more significant differences of the levels of thiols: Hcy [MTHFR: CT (C677T) and GG (G1793A); MTR, AG (A2756G)], Met [MTR, AA (A2756G)], Cys [MTR, AG (A2756G)], and Met/Hcy [MTHFR: CC, CT (C677T) and AA (A1298C), and GG (G1793A); MTHFD1 AA(G1958A); MTR AA(A2756G)]. Significant differences in the levels of Cys/Hcy, MTHFD1 GA (G1958) were varied between AD and PD groups. The results indicate that of the enzymes studied only polymorphisms of folate-dependent enzyme MTHFD1 have pointed to significant differences in intensity of turnover of circulating thiols between AD and PD patients.

The effect of cAMP and some sulphur compounds upon the activity of mercaptopyruvate sulphurtransferase and rhodanese in mouse liver

86%

Wrobel M. , Frendo J.

Folia Biologica

1992

tom 40

nr 1-2

11-14

The aim of the experiments was to evaluate the effect of administration of cysteine, methionine, thiocystine, and thiosulphate upon the activity of mercaptopyruvate sulphurtransferase (MPST) and rhodanese in mouse liver. It was found that rhodanese activity increased following thiocystine and methionine administration and showed a smaller increase after cysteine and thiosulphate. The MPST activity significantly increased after cysteine and to a lesser extent after thiocystine and thiosulphate. On the other hand, methionine seemed to exert no effect upon the enzymatic activity. The results suggested that methionine metabolic cycle in mouse liver proceeded from cysteine to sulphane sulphur as thiocystine and, therefore, these three compounds increased rhodanese activity. Thiosulphate seemed rather to be involved in metabolic changes related to maintaining the stability of the physiological thiosulphate level and activated both the enzymes.

Alzheimer's beta-amyloid peptide as a source of neurotoxic free radicals: the role of structural effects

58%

Pogocki D.

Acta Neurobiologiae Experimentalis

2003

tom 63

nr 2

131-145

This mini review gives a brief overview over the oxidation mechanism of methionine (Met), relevant for processes which may lead to the oxidation of amyloid beta-peptide (betaAP), involved in the pathogenesis of Alzheimer?s disease. The Cu II-catalysed oxidation of C-terminal Met 35 in AP depends on the secondary structure of the peptide. That seems to be the key to the known propensities of this peptide to form reactive oxygen species and free radicals. The pro-oxidant character of betaAP is not associated with its -beta sheet insoluble form. On the contrary, the alpha-helically organised structure is responsible for betaAP redox-related cytotoxicity.