Nomura T, Nakayama N, Murata T, Akazawa T. Biosynthesis of starch in chloroplasts.
PLANT PHYSIOLOGY 1967;
42:327-32. [PMID:
4292567 PMCID:
PMC1086537 DOI:
10.1104/pp.42.3.327]
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Abstract
The enzymic synthesis of ADP-glucose and UDP-glucose by chloroplastic pyrophosphorylase of bean and rice leaves has been demonstrated by paper chromatographic techniques. In both tissues, the activity of UDP-glucose-pyrophosphorylase was much higher than ADP-glucose-pyrophosphorylase. Glycerate-3-phosphate, phosphoenolpyruvate and fructose-1,6-diphosphate did not stimulate ADP-glucose formation by a pyrophosphorylation reaction. The major metabolic pathway for UDP-glucose utilization appears to be the synthesis of either sucrose or sucrose-P. On the other hand, a specific precursor role of ADP-glucose for synthesizing chloroplast starch by the ADP-glucose-starch transglucosylase reaction is supported by the coupled enzyme system of ADP-glucose-pyrophosphorylase and transglucosylase, isolated from chloroplasts. None of the glycolytic intermediates stimulated the glucose transfer in the enzyme sequence of reaction system employed.
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