sddx 2007/09/19
Manganese poisoning and the attack of trivalent manganese upon catecholamines [img]https://www.instrument.com.cn/bbs/images/affix.gif[/img][url=http://www.instrument.com.cn/bbs/download.asp?ID=64333]Manganese poisoning and the attack of trivalent manganese upon catecholamines[/url]
hanxm 2007/09/18
很抱歉,只能查到这些.国内很多电子期刊都只购买1995年以后的刊. Archives of Biochemistry and Biophysics 1987.Volume 256,Issue2 Manganese poisoning and the attack of trivalent manganese upon catecholamines Pages 638-650 Frederick S. Archibald and Curtis Tyree Abstract Human manganese poisoning or manganism results in damage to the substantia nigra of the brain stem, a drop in the level of the inhibitory neurotransmitter dopamine, and symptoms resembling those of Parkinson's disease. Manganic (Mn3+) manganese ions were shown to be readily produced by O−2 in vitro and spontaneously under conditions obtainable in the human brain. Mn3+ as its pyrophosphate complex was shown to rapidly and efficiently carry out four-electron oxidations of dopamine, its precursor dopa (3,4-dihydroxyphenylalanine), and its biosynthetic products epinephrine and norepinephrine. Mn3+-pyrophosphate was shown to specifically attack dihydroxybenzene derivatives, but only those with adjacent hydroxyl groups. Further, the addition of Mn2+-pyrophosphate to a system containing a flux of O−2 and dopamine greatly accelerated the oxidation of dopamine. The oxidation of dopamine by Mn3+ neither produced nor required O2, and Mn3+ was far more efficient than Mn2+, Mn4+ (MnO2), O−2, or H2O2 in oxidizing the catecholamines. A higher oxidation state, Mn(OH)3, formed spontaneously in an aqueous Mn(OH)2 precipitate and slowly darkened, presumably being oxidized to MnO2. Like reagent MnO2, it weakly catalyzed dopamine oxidation. However, both MnO2 preparations showed dramatically increased abilities to oxidize dopamine in the presence of pyrophosphate due to enhancement of the spontaneous formation of the Mn3+ complex. These results strongly suggest that the pathology of manganese neurotoxicity is dependent on the ease with which simple Mn3+ complexes are formed under physiological conditions and the efficiency with which they destroy catecholamines.
hanxm
第2楼2007/09/18
很抱歉,只能查到这些.国内很多电子期刊都只购买1995年以后的刊.
Archives of Biochemistry and Biophysics 1987.Volume 256,Issue2 Manganese poisoning and the attack of trivalent manganese upon catecholamines
Pages 638-650
Frederick S. Archibald and Curtis Tyree
Abstract
Human manganese poisoning or manganism results in damage to the substantia nigra of the brain stem, a drop in the level of the inhibitory neurotransmitter dopamine, and symptoms resembling those of Parkinson's disease. Manganic (Mn3+) manganese ions were shown to be readily produced by O−2 in vitro and spontaneously under conditions obtainable in the human brain. Mn3+ as its pyrophosphate complex was shown to rapidly and efficiently carry out four-electron oxidations of dopamine, its precursor dopa (3,4-dihydroxyphenylalanine), and its biosynthetic products epinephrine and norepinephrine. Mn3+-pyrophosphate was shown to specifically attack dihydroxybenzene derivatives, but only those with adjacent hydroxyl groups. Further, the addition of Mn2+-pyrophosphate to a system containing a flux of O−2 and dopamine greatly accelerated the oxidation of dopamine. The oxidation of dopamine by Mn3+ neither produced nor required O2, and Mn3+ was far more efficient than Mn2+, Mn4+ (MnO2), O−2, or H2O2 in oxidizing the catecholamines. A higher oxidation state, Mn(OH)3, formed spontaneously in an aqueous Mn(OH)2 precipitate and slowly darkened, presumably being oxidized to MnO2. Like reagent MnO2, it weakly catalyzed dopamine oxidation. However, both MnO2 preparations showed dramatically increased abilities to oxidize dopamine in the presence of pyrophosphate due to enhancement of the spontaneous formation of the Mn3+ complex. These results strongly suggest that the pathology of manganese neurotoxicity is dependent on the ease with which simple Mn3+ complexes are formed under physiological conditions and the efficiency with which they destroy catecholamines.
sddx
第3楼2007/09/19
Manganese poisoning and the attack of trivalent manganese upon catecholamines
Manganese poisoning and the attack of trivalent manganese upon catecholamines
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