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Lessened malate inhibition of guard‐cell phospho enol pyruvate carboxylase velocity during stomatal opening
Author(s) -
Zhang Shu Qiu,
Outlaw William H,
Chollet Raymond
Publication year - 1994
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(94)00916-3
Subject(s) - guard cell , phosphoenolpyruvate carboxylase , vicia faba , pyruvate carboxylase , c4 photosynthesis , biochemistry , chemistry , phosphoenolpyruvate carboxykinase , botany , biology , biophysics , photosynthesis , enzyme
Leaflets of Vicia faba with closed stomata or with opening stomata were freeze‐dried. Excised guard‐cell pairs were assayed individually under suboptimal conditions (pH 7.1 and subsaturating substrate) for phospho enol pyruvate carboxylase (PEPC; EC 4.1.1.31) using quantitative histochemical procedures. l ‐Malate, 400 μM, significantly inhibited guard‐cell PEPC activity of closed stomata but not that of opening stomata. We postulate that the lessened sensitivity of guard‐cell PEPC activity to malate inhibition is an important regulatory feature of stomatal opening, which is associated with malate accumulation.