Korean
Albanian
Arabic
Armenian
Azerbaijani
Belarusian
Bengali
Bosnian
Catalan
Czech
Danish
Deutsch
Dutch
English
Estonian
Finnish
Français
Greek
Haitian Creole
Hebrew
Hindi
Hungarian
Icelandic
Indonesian
Irish
Italian
Japanese
Korean
Latvian
Lithuanian
Macedonian
Mongolian
Norwegian
Persian
Polish
Portuguese
Romanian
Russian
Serbian
Slovak
Slovenian
Spanish
Swahili
Swedish
Turkish
Ukrainian
Vietnamese
Български
中文(简体)
中文(繁體)
Philosophical Transactions of the Royal Society B: Biological Sciences 2000-Oct

Ascorbate biosynthesis and function in photoprotection.

등록 된 사용자 만 기사를 번역 할 수 있습니다.
로그인 / 가입
링크가 클립 보드에 저장됩니다.
N Smirnoff

키워드

요약

Ascorbate (vitamin C) can reach very high concentrations in chloroplasts (20-300 mM). The pool size in leaves and chloroplasts increases during acclimation to high light intensity and the highest concentrations recorded are in high alpine plants. Multiple functions for ascorbate in photosynthesis have been proposed, including scavenging of active oxygen species generated by oxygen photoreduction and photorespiration, regeneration of alpha-tocopherol from alpha-tocopheryl radicals, cofactor for violaxanthin de-epoxidase and donation of electrons to photosystem II. Hydrogen peroxide scavenging is catalysed by ascorbate peroxidase (Mehler peroxidase reaction) and the subsequent regeneration of ascorbate by reductant derived from photosystem I allows electron flow in addition to that used for CO2 assimilation. Ascorbate is synthesized from guanosine diphosphate-mannose via L-galactose and L-galactono-1,4-lactone. The last step, catalysed by L-galactono-1,4-lactone dehydrogenase, is located on the inner mitochondrial membrane and uses cytochrome c as electron acceptor. L-galactono-1,4-lactone oxidation to ascorbate by intact leaves is faster in high-light acclimated leaves and is also enhanced by high light, suggesting that this step contributes to the control of pool size by light. Ascorbate-deficient Arabidopsis thaliana vtc mutants are hypersensitive to a number of oxidative stresses including ozone and ultraviolet B radiation. Further investigation of these mutants shows that they have reduced zeaxanthin-dependent non-photochemical quenching, confirming that ascorbate is the cofactor for violaxanthin de-epoxidase and that availability of thylakoid lumen ascorbate could limit this reaction. The vtc mutants are also more sensitive to photo-oxidation imposed by combined high light and salt treatments.

페이스 북
페이지에 가입하세요

과학이 뒷받침하는 가장 완벽한 약초 데이터베이스

  • 55 개 언어로 작동
  • 과학이 뒷받침하는 약초 치료제
  • 이미지로 허브 인식
  • 인터랙티브 GPS지도-위치에 허브 태그 지정 (출시 예정)
  • 검색과 관련된 과학 출판물 읽기
  • 효과로 약초 검색
  • 관심사를 정리하고 뉴스 연구, 임상 실험 및 특허를 통해 최신 정보를 확인하세요.

증상이나 질병을 입력하고 도움이 될 수있는 약초에 대해 읽고 약초를 입력하고 사용되는 질병과 증상을 확인합니다.
* 모든 정보는 발표 된 과학 연구를 기반으로합니다.

Google Play badgeApp Store badge