Regulation of violaxanthin de-epoxidase activity by pH and ascorbate concentration
(1995) In Photosynthesis Research 45(2). p.169-175- Abstract
- The activity of violaxanthin de-epoxidase has been studied both in isolated thylakoids and after partial purification, as a function of pH and ascorbate concentration. We demonstrate that violaxanthin de-epoxidase has a Km for ascorbate that is strongly dependent on pH, with values of 10, 2.5, 1.0 and 0.3 mM at pH 6.0, 5.5, 5.0 and 4.5, respectively. These values can be expressed as a single Km±0.1±0.02 mM for the acid form of ascorbate. Release of the protein from the thylakoids by sonication was also found to be strongly pH dependent with a cooperativity of 4 with respect to protons and with an inflexion point at pH 6.7. These results can explain some of the discrepancies reported in the literature and provide a more consistent view of... (More)
- The activity of violaxanthin de-epoxidase has been studied both in isolated thylakoids and after partial purification, as a function of pH and ascorbate concentration. We demonstrate that violaxanthin de-epoxidase has a Km for ascorbate that is strongly dependent on pH, with values of 10, 2.5, 1.0 and 0.3 mM at pH 6.0, 5.5, 5.0 and 4.5, respectively. These values can be expressed as a single Km±0.1±0.02 mM for the acid form of ascorbate. Release of the protein from the thylakoids by sonication was also found to be strongly pH dependent with a cooperativity of 4 with respect to protons and with an inflexion point at pH 6.7. These results can explain some of the discrepancies reported in the literature and provide a more consistent view of zeaxanthin formation in vivo. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/1494411
- author
- Bratt, Charlotte Eva ; Arvidsson, Per-Ola ; Carlsson, Marie and Åkerlund, Hans-Erik LU
- organization
- publishing date
- 1995
- type
- Contribution to journal
- publication status
- published
- subject
- in
- Photosynthesis Research
- volume
- 45
- issue
- 2
- pages
- 169 - 175
- publisher
- Springer
- external identifiers
-
- scopus:34249758236
- ISSN
- 0166-8595
- DOI
- 10.1007/BF00032588
- language
- English
- LU publication?
- yes
- id
- bc450253-4efc-4fd9-8b34-4d938be80ba2 (old id 1494411)
- date added to LUP
- 2016-04-01 16:11:11
- date last changed
- 2021-02-07 05:29:13
@article{bc450253-4efc-4fd9-8b34-4d938be80ba2, abstract = {{The activity of violaxanthin de-epoxidase has been studied both in isolated thylakoids and after partial purification, as a function of pH and ascorbate concentration. We demonstrate that violaxanthin de-epoxidase has a Km for ascorbate that is strongly dependent on pH, with values of 10, 2.5, 1.0 and 0.3 mM at pH 6.0, 5.5, 5.0 and 4.5, respectively. These values can be expressed as a single Km±0.1±0.02 mM for the acid form of ascorbate. Release of the protein from the thylakoids by sonication was also found to be strongly pH dependent with a cooperativity of 4 with respect to protons and with an inflexion point at pH 6.7. These results can explain some of the discrepancies reported in the literature and provide a more consistent view of zeaxanthin formation in vivo.}}, author = {{Bratt, Charlotte Eva and Arvidsson, Per-Ola and Carlsson, Marie and Åkerlund, Hans-Erik}}, issn = {{0166-8595}}, language = {{eng}}, number = {{2}}, pages = {{169--175}}, publisher = {{Springer}}, series = {{Photosynthesis Research}}, title = {{Regulation of violaxanthin de-epoxidase activity by pH and ascorbate concentration}}, url = {{http://dx.doi.org/10.1007/BF00032588}}, doi = {{10.1007/BF00032588}}, volume = {{45}}, year = {{1995}}, }