Flux Control Analysis of the Rate of Photosynthetic CO2 Assimilation

2009 ◽  
pp. 349-360
Author(s):  
Ian E. Woodrow
Keyword(s):  
Co2 Assimilation ◽  
Control Analysis ◽  
Flux Control ◽  
Photosynthetic Co2 Assimilation

Control analysis of photosynthetic sucrose synthesis: assignment of elasticity coefficients and flux-control coefficients to the cytosolic fructose 1,6-bisphosphatase and sucrose phosphate synthase

1989 ◽  
Vol 323 (1216) ◽  
pp. 327-338 ◽  
Keyword(s):  
Sucrose Phosphate Synthase ◽  
Control Analysis ◽  
Sucrose Synthesis ◽  
Flux Control ◽  
Fructose 1,6 Bisphosphatase ◽  
Flux Control Coefficients ◽  
Sucrose Phosphate ◽  
Control Coefficients ◽  
Phosphate Synthase

The use of elasticity coefficients and flux-control coefficients in a quantitative treatment of control is discussed, with photosynthetic sucrose synthesis as an example. Experimental values for elasticities for the cytosolic fructose 1,6-bisphosphatase and sucrose phosphate synthase are derived from their in vitro properties, and from an analysis of the in vivo relation between fluxes and metabolite levels. An empirical factor α , describing the response of the fructose 2,6-bisphosphate regulator cycle to fructose 6-phosphate is described, and an expression is derived relating α to the elasticities of the enzymes involved in this regulator cycle. The in vivo values for elasticities and α are then used in a modified form of the connectivity theorem to estimate the flux control coefficients of the cytosolic fructose 1,6-bisphosphatase and sucrose phosphate synthase during rapid photosynthetic sucrose synthesis.

Two proteins function in the regulation of photosynthetic CO2 assimilation in chloroplasts

Nature ◽  
1976 ◽  
Vol 263 (5574) ◽  
pp. 257-258 ◽  
Author(s):  
PETER SCHÜRMANN ◽  
RICARDO A. WOLOSIUK ◽  
VICKI D. BREAZEALE ◽  
BOB B. BUCHANAN
Keyword(s):  
Co2 Assimilation ◽  
Photosynthetic Co2 Assimilation

scholarly journals Metabolic control analysis of biochemical pathways based on a thermokinetic description of reaction rates

1997 ◽  
Vol 321 (1) ◽  
pp. 133-138 ◽  
Author(s):  
Jens NIELSEN
Keyword(s):  
Metabolic Control ◽  
Reaction Rate ◽  
Reaction Rates ◽  
Rate Function ◽  
Metabolic Control Analysis ◽  
Control Analysis ◽  
Flux Control ◽  
Biochemical Pathways ◽  
Flux Control Coefficients

Metabolic control analysis is a powerful technique for the evaluation of flux control within biochemical pathways. Its foundation is the elasticity coefficients and the flux control coefficients (FCCs). On the basis of a thermokinetic description of reaction rates it is here shown that the elasticity coefficients can be calculated directly from the pool levels of metabolites at steady state. The only requirement is that one thermodynamic parameter be known, namely the reaction affinity at the intercept of the tangent in the inflection point of the curve of reaction rate against reaction affinity. This parameter can often be determined from experiments in vitro. The methodology is applicable only to the analysis of simple two-step pathways, but in many cases larger pathways can be lumped into two overall conversions. In cases where this cannot be done it is necessary to apply an extension of the thermokinetic description of reaction rates to include the influence of effectors. Here the reaction rate is written as a linear function of the logarithm of the metabolite concentrations. With this type of rate function it is shown that the approach of Delgado and Liao [Biochem. J. (1992) 282, 919–927] can be much more widely applied, although it was originally based on linearized kinetics. The methodology of determining elasticity coefficients directly from pool levels is illustrated with an analysis of the first two steps of the biosynthetic pathway of penicillin. The results compare well with previous findings based on a kinetic analysis.

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