Studies on the regulation of chloroplast fructose-1,6-bisphosphatase. Activation by fructose 1,6-bisphosphate

Chloroplast fructose-1,6-bisphosphatase d-fructose 1,6-bisphosphate 1-phosphohydrolase, EC 3.1.3.11) isolated from spinach leaves, was activated by preincubation with fructose 1,6-bisphosphate. The rate of activation was slower than the rate of catalysis, and dependent upon the temperature and the c...

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Autores principales: Chehebar, C., Wolosiuk, R.A.
Formato: JOUR
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Acceso en línea:http://hdl.handle.net/20.500.12110/paper_00052744_v613_n2_p429_Chehebar
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Sumario:Chloroplast fructose-1,6-bisphosphatase d-fructose 1,6-bisphosphate 1-phosphohydrolase, EC 3.1.3.11) isolated from spinach leaves, was activated by preincubation with fructose 1,6-bisphosphate. The rate of activation was slower than the rate of catalysis, and dependent upon the temperature and the concentration of fructose 1,6-bisphosphate. The addition of other sugar diphosphates, sugar monophosphates or intermediates of the reductive pentose phosphate cycle neither replaced fructose 1,6-bisphosphate nor modified the activation process. Upon activation with the effector the enzyme was less sensitive to trypsin digestion and insensitive to mercurials. The activity of chloroplast fructose-1,6-bisphosphatase, preincubated with fructose 1,6-bisphosphate, returned to its basal activity after the concentration of the effector was lowered in the preincubation mixture. The results provide evidence that fructose-1,6-bisophosphatase resembles other regulatory enzymes involved in photosynthetic CO2 assimilation in its activation by chloroplast metabolites. © 1980.