Ascorbic acid metabolism and functions: A comparison of plants and mammals.
Ascorbic acid metabolism and functions: A comparison of plants and mammals.
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DOI：
10.1016/j.freeradbiomed.2018.03.033
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发表时间：
2018-07
影响因子：
7.4
通讯作者：
Smirnoff N
中科院分区：
文献类型：
--
作者：
Smirnoff N
Ascorbic acid is synthesised by eukaryotes, the known exceptions being primates and some other animal groups which have lost functional gulonolactone oxidase. Prokaryotes do not synthesise ascorbate and do not need an ascorbate supply, so the functions that are essential for mammals and plants are not required or are substituted by other compounds. The ability of ascorbate to donate electrons enables it to act as a free radical scavenger and to reduce higher oxidation states of iron to Fe2+. These reactions are the basis of its biological activity along with the relative stability of the resulting resonance stabilised monodehydroascorbate radical. The importance of these properties is emphasised by the evolution of at least three biosynthetic pathways and production of an ascorbate analogue, erythroascorbate, by fungi. The iron reducing activity of ascorbate maintains the reactive centre Fe2+ of 2-oxoglutarate-dependent dioxygenases (2-ODDs) thus preventing inactivation. These enzymes have diverse functions and, recently, the possibility that ascorbate status in mammals could influence 2-ODDs involved in histone and DNA demethylation thereby influencing stem cell differentiation and cancer has been uncovered. Ascorbate is involved in iron uptake and transport in plants and animals. While the above biochemical functions are shared between mammals and plants, ascorbate peroxidase (APX) is an enzyme family limited to plants and photosynthetic protists. It provides these organisms with increased capacity to remove H2O2 produced by photosynthetic electron transport and photorespiration. The Fe reducing activity of ascorbate enables hydroxyl radical production (pro-oxidant effect) and the reactivity of dehydroascorbate (DHA) and reaction of its degradation products with proteins (dehydroascorbylation and glycation) is potentially damaging. Ascorbate status influences gene expression in plants and mammals but at present there is little evidence that it acts as a specific signalling molecule. It most likely acts indirectly by influencing the redox state of thiols and 2-ODD activity. However, the possibility that dehydroascorbylation is a regulatory post-translational protein modification could be explored. The function and metabolism of ascorbate is compared between plants and mammals. Ascorbate readily reduces radicals and Fe/Cu. Ascorbate is synthesised by plants, protists and animals via different pathways. Fungi synthesise the analogue D-erythroascorbate. Plants and photosynthetic protists use ascorbate peroxidase to remove H2O2.
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影响因子：
4.6
作者：
Bodra N;Young D;Astolfi Rosado L;Pallo A;Wahni K;De Proft F;Huang J;Van Breusegem F;Messens J
通讯作者：
Messens J
DOI：
10.1073/pnas.78.11.6858
发表时间：
1981-01-01
期刊：
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA-BIOLOGICAL SCIENCES
影响因子：
--
作者：
AMES, BN;CATHCART, R;HOCHSTEIN, P
通讯作者：
HOCHSTEIN, P
影响因子：
5.3
作者：
Cárcamo, JM;Pedraza, A;Golde, DW
通讯作者：
Golde, DW
影响因子：
6.9
作者：
Conklin, Patricia L.;DePaolo, Dennis;Buckenmeyer, Gail
通讯作者：
Buckenmeyer, Gail
影响因子：
64.8
作者：
Agathocleous M;Meacham CE;Burgess RJ;Piskounova E;Zhao Z;Crane GM;Cowin BL;Bruner E;Murphy MM;Chen W;Spangrude GJ;Hu Z;DeBerardinis RJ;Morrison SJ
通讯作者：
Morrison SJ