Light Activation of NADP-Malate Dehydrogenase in Guard Cell Protoplasts from Vicia faba L

Autor:	Kiyoshi Tanaka, Kiyoshi Gotow, Koh Kobayashi, Noriaki Kondo, Kunihiko Syōno
Rok vydání:	1985
Předmět:	biology Physiology food and beverages Dehydrogenase DCMU Plant Science Enzyme assay Vicia faba Chloroplast chemistry.chemical_compound Biochemistry chemistry Guard cell Chlorophyll Genetics biology.protein Phosphoenolpyruvate carboxylase
Zdroj:	Plant Physiology. 79:829-832
ISSN:	1532-2548 0032-0889
DOI:	10.1104/pp.79.3.829
Popis:	Light-induced swelling of guard cell protoplasts (GCP) from Vicia faba was accompanied by increases in content of K(+) and malate. DCMU inhibited the increase of K(+) and malate, and consequently swelling.Effect of light on the activity of selected enzymes that take part in malate formation was studied. When isolated GCP were illuminated, NADP-malate dehydrogenase (NADP-MDH) was activated, and the activity reached a maximum within 5 minutes. The enzyme activity underwent 5- to 6-fold increase in the light. Upon turning off the light, the enzyme was inactivated in 5 minutes NAD-MDH and phosphoenolpyruvate carboxylase (PEPC) were not influenced by light. The rapid light activation of NADP-MDH was inhibited by DCMU, suggesting that the enzyme was activated by reductants from the linear electron transport in chloroplasts. An enzyme localization study by differential centrifugation indicates that NADP-MDH is located in the chloroplasts, NAD-MDH in the cytosol and mitochondria, and PEPC in the cytosol. After light activation, the activity of NADP-MDH in guard cells was 10 times that in mesophyll cells on a chlorophyll basis. The physiological significance of light-dependent activation of NADP-MDH in guard cells is discussed in relation to stomatal movement.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::b3bd2337a3aff05f6e7f36f6bc5004ea https://doi.org/10.1104/pp.79.3.829 Zobrazit plný text záznamu