Photosynthetic Characteristics of C_3-C_4 Intermediate Flaveria Species II. : Kinetic Properties of Phosphoenolpyruvate Carboxylase from C_3-C_4 and C_3-C_4 Intermediate Species

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概要

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• The kinetic properties of phosphoenolpyruvate (PEP) carboxylase have been studied among several Flaveria species: the C_3 species F. cronquistii, the C_3-C_4 species F. pubescens and F. linearis, and the C_4 species F, trinervia. At either pH 7 or 8, the maximum activities (in μmol・mg Chl^<-1>・h^<-1>) for F. pubescens and linearis (187-513) were intermediate to those of the C_3 species (12-19) and the C_4 species (2,182-2,627). The response curves of velocity versus PEP concentration were hyperbolic for the C_3 and C_3-C_4 species at either pH 7 or 8 while they were sigmoidal for the C_4 species at pH 7 and hyperbolic at pH 8. The Km values for PEP determined from reciprocal plots were lowest in the C_3 species, and of intermediate value in the C_3-C_4 species compared to the K' values of the C_4 species determined from Hill plots at either pH 7 or 8. Glucose-6-phosphate (G6P) decreased the Km values for PEP at both pH 7 and 8 in the C_3 and C_3-C_4 species. In the C_4 species, G6P decreased the K'values at pH 8 but increased the K' values at pH 7. In all cases, G6P had its effect by influencing the activity at limiting PEP concentrations with little or no effect on the maximum activity. At pH 8 and limiting concentrations of PEP the degree of stimulation of the activity by G6P was greatest in the C_4 species, intermediate in F, linearis, a C_3-C_4 species, and lowest in the C_3 species. In several respects, the PEP carboxylases of the C_3-C_4 Flaveria. species have properties intermediate to those of the C_3 and C_4 species.

• 日本植物生理学会の論文

著者

• Edwards G.e.

  Department Of Botany Washington State University:institute Of Biological Chemistry Washington State

• Nakamoto H.

  Department of Botany, Washington State University

• Ku M.S.B.

  Department of Botany, Washington State University

• Ku M.s.b.

  Department Of Botany Washington State University

• Nakamoto H.

  Department Of Botany Washington State University

関連論文

• Distribution of enzymes related to C_3 and C_4 pathway of photosynthesis between mesophyll and bundle sheath cells of Panicum hians and Panicum milioides
• Photosynthetic Characteristics of C_3-C_4 Intermediate Flaveria Species II. : Kinetic Properties of Phosphoenolpyruvate Carboxylase from C_3-C_4 and C_3-C_4 Intermediate Species
• Differences in cold lability of pyruvate,Pi dikinase among C_4 species
• Photosynthetic efficiency of Panicum hians and Panicum milioides in relation to C_3 and C_4 plants
• Glycolate synthesis in a C_3, C_4 and intermediate photosynthetic plant type
• Use of inhibitors to distinguish between C_4 acid decarboxylation mechanisms in bundle sheath cells of C_4 plants

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