Enzymes of Carbohydrate Metabolism in the Developing Rice Grain
Open Access
- 1 November 1975
- journal article
- Published by Oxford University Press (OUP) in Plant Physiology
- Vol. 56 (5) , 579-583
- https://doi.org/10.1104/pp.56.5.579
Abstract
The levels of reducing and nonreducing sugars, starch, soluble protein, and selected enzymes involved in the metabolism of sucrose, glucose-1-P, and glucose nucleotides were assayed in dehulled developing rice grains (Oryza sativa L. line IR1541-76-3) during the first 3 weeks after flowering. The level of reducing sugars in the grain was highest 5 to 6 days after flowering. The level of nonreducing sugars and the rate of starch accumulation were maximum 11 to 12 days after flowering, when the level of soluble protein was also the highest. The activities of bound and free invertase, sucrose-UDP and sucrose-ADP glucosyltransferases, hexokinase, phosphoglucomutase, nucleoside diphosphokinase, and UDP-glucose and ADP-glucose pyrophosphorylases were high throughout starch deposition, and were maximum, except for nucleoside diphosphokinase which did not increase in activity, between 8 and 18 days after flowering. Soluble primed phosphorylase and ADP glucose-α-glucosyltransferase (starch synthetase) were both present during starch accumulation. Phosphorylase activity was at least 2-fold that of soluble starch synthetase but the synthetase followed more closely the rate of starch accumulation in the grain. The activity of starch synthetase bound to the starch granule also increased progressively with increased starch content of the grain.Keywords
This publication has 17 references indexed in Scilit:
- ADPG SYNTHETASE AND ADPG‐α‐GLUCAN 4‐GLUCOSYL TRANSFERASE: ENZYMES INVOLVED IN BACTERIAL GLYCOGEN AND PLANT STARCH SYNTHESIS*Annals of the New York Academy of Sciences, 1973
- THE ROLE OF PHOSPHORYLASE IN STARCH BIOSYNTHESIS*Annals of the New York Academy of Sciences, 1973
- THE PHOSPHORYLASES OF DEVELOPING MAIZE SEEDS*Annals of the New York Academy of Sciences, 1973
- De Novo SYNTHESIS OF BACTERIAL GLYCOGEN AND PLANT STARCH BY ADPG:α‐GLUCAN 4‐GLUCOSYL TRANSFERASE*Annals of the New York Academy of Sciences, 1973
- FUNDAMENTAL PROBLEMS IN THE BIOSYNTHESIS OF STARCH GRANULESAnnals of the New York Academy of Sciences, 1973
- Movement of 14C-Labeled Assimilates into Kernels of Zea mays LPlant Physiology, 1972
- Invertase Activity in Normal and Mutant Maize Endosperms during DevelopmentPlant Physiology, 1971
- Enzymes of Starch Metabolism in the Developing Rice GrainPlant Physiology, 1970
- Enzymes of Carbohydrate Metabolism in the Developing Endosperm of MaizePlant Physiology, 1970
- Enzymic Mechanism of Starch Synthesis in Ripening Rice GrainsPlant Physiology, 1964