Regulation of C4 photosynthesis: modulation of mitochondrial NAD-malic enzyme by adenylates |
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Authors: | R T Furbank A Agostino M D Hatch |
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Affiliation: | CSIRO, Division of Plant Industry, Canberra City, Australia. |
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Abstract: | Effects of adenylates on the activity of mitochondrial NAD-malic enzyme from NAD-malic-enzyme (NAD-ME)-type and phosphoenolpyruvate-carboxykinase-(PKC)-type C4 plants are examined. At physiological concentrations, ATP, ADP, and AMP all inhibit the enzyme from Atriplex spongiosa and Panicum miliaceum (NAD-ME-type plants), with ATP the most inhibitory species. The degree of inhibition is greater with subsaturating levels of activator, malate, and Mn2+. NAD-malic enzyme from Urochloa panicoides (PCK-type) is activated by ATP (up to 10-fold) and inhibited by ADP and AMP. These effects are discussed in relation to regulation of C4 photosynthesis. |
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