Departments of Biology and Pharmacology (1137), Washington University Division of Biology and Biomedical Sciences, Saint Louis, Missouri 63130.
Plant Physiol. 1978 Oct;62(4):648-52. doi: 10.1104/pp.62.4.648.
From the maximum rate of malate accumulation in Vicia faba L. guard cells during stomatal opening the maximum rate of organic anion synthesis is calculated to be 200 millimoles per kilogram dry weight per hour. A minimum estimate for the phosphoenolpyruvate (PEP) carboxylase-catalyzed reaction in guard cells is 650 millimoles per kilogram dry weight per hour which is significantly higher than in any other leaf tissue. The apparent K(mpep) of the guard cell enzyme is 60 mum at pH 8.7, but is probably higher at lower pH. The concentration of PEP in guard cells was 270mum (=2.2 x 10(-15) moles/guard cell pair) during anion synthesis. These results support the possibility that the carboxylation of PEP is the anaplerotic step in guard cells.
从蚕豆保卫细胞在气孔开放时积累苹果酸的最大速率计算，有机阴离子合成的最大速率为每小时每公斤干重 200 毫摩尔。对保卫细胞中磷酸烯醇丙酮酸（PEP）羧化酶催化反应的最小估计值为每小时每公斤干重 650 毫摩尔，这明显高于任何其他叶片组织。保卫细胞酶的表观 K(mpep)在 pH8.7 时为 60μm，但在较低 pH 值时可能更高。在阴离子合成过程中，保卫细胞中的 PEP 浓度为 270μm（=2.2×10^(-15)摩尔/保卫细胞对）。这些结果支持了 PEP 羧化作用是保卫细胞中氨同化作用的补料步骤的可能性。
