This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via CrossRef Citing Articles via Web of Science (72) Citing Articles via Google Scholar Google Scholar Articles by Doehlert, D. C. Articles by Felker, F. C. Search for Related Content PubMed PubMed Citation Articles by Doehlert, D. C. Articles by Felker, F. C. Agricola Articles by Doehlert, D. C. Articles by Felker, F. C.

Metabolism and Enzymology

Enzymes of Sucrose and Hexose Metabolism in Developing Kernels of Two Inbreds of Maize

Seed Biosynthesis Research Unit, United States Department of Agriculture/Agricultural Research Service Northern Regional Research Center, Peoria, Illinois 61604

Tissue distribution and activity of enzymes involved in sucrose and hexose metabolism were examined in kernels of two inbreds of maize (Zea mays L.) at progressive stages of development. Levels of sugars and starch were also quantitated throughout development. Enzyme activities studied were: ATP-linked fructokinase, UTP-linked fructokinase, ATP-linked glucokinase, sucrose synthase, UDP-Glc pyrophosphorylase, UDP-Glc dehydrogenase, PPi-linked phosphofructokinase, ATP-linked phosphofructokinase, NAD-dependent sorbitol dehydrogenase, NADP-dependent 6-P-gluconate dehydrogenase, NADP-dependent Glc-6-P dehydrogenase, aldolase, phosphoglucoisomerase, and phosphoglucomutase. Distribution of invertase activity was examined histochemically. Hexokinase and ATP-linked phosphofructokinase activities were the lowest among these enzymes and it is likely that these enzymes may regulate the utilization of sucrose in developing maize kernels. Most of the hexokinase activity was found in the endosperm, but the embryo had high activity on a dry weight basis. The endosperm, which stores primarily starch, contained high PPi-linked phosphofructokinase and low ATP-linked phosphofructokinase activities, whereas the embryo, which stores primarily lipids, had much higher ATP-linked phosphofructokinase activity than did the endosperm. It is suggested that PPi required by UDP-Glc pyrophosphorylase and PPi-linked phosphofructokinase in the endosperm may be supplied by starch synthesis. Sorbitol dehydrogenase activity was largely restricted to the endosperm, whereas 6-P-gluconate and Glc-6-P dehydrogenase activities were highest in the base and pericarp. A possible metabolic pathway by which sucrose is converted into starch is proposed.

This article has been cited by other articles:

				A. Muscolo and M. Sidari Carboxyl and Phenolic Humic Fractions Affect Pinus Nigra Callus Growth and Metabolism Soil Sci. Soc. Am. J., May 13, 2009; 73(4): 1119 - 1129. [Abstract] [Full Text] [PDF]

				E. Grafahrend-Belau, F. Schreiber, D. Koschutzki, and B. H. Junker Flux Balance Analysis of Barley Seeds: A Computational Approach to Study Systemic Properties of Central Metabolism Plant Physiology, January 1, 2009; 149(1): 585 - 598. [Abstract] [Full Text] [PDF]

				H. Fallahi, G. N. Scofield, M. R. Badger, W. S. Chow, R. T. Furbank, and Y.-L. Ruan Localization of sucrose synthase in developing seed and siliques of Arabidopsis thaliana reveals diverse roles for SUS during development J. Exp. Bot., September 1, 2008; 59(12): 3283 - 3295. [Abstract] [Full Text] [PDF]

				A. Muscolo, M. Sidari, E. Attina, O. Francioso, V. Tugnoli, and S. Nardi Biological Activity of Humic Substances Is Related to Their Chemical Structure Soil Sci. Soc. Am. J., January 1, 2007; 71(1): 75 - 85. [Abstract] [Full Text] [PDF]

				C. Després, C. DeLong, S. Glaze, E. Liu, and P. R. Fobert The Arabidopsis NPR1/NIM1 Protein Enhances the DNA Binding Activity of a Subgroup of the TGA Family of bZIP Transcription Factors PLANT CELL, February 1, 2000; 12(2): 279 - 290. [Abstract] [Full Text]

				E.P. Wilhelm, R.E. Mullen, P.L. Keeling, and G.W. Singletary Heat Stress during Grain Filling in Maize: Effects on Kernel Growth and Metabolism Crop Sci., November 1, 1999; 39(6): 1733 - 1741. [Abstract] [Full Text]

				G. Creissen, J. Firmin, M. Fryer, B. Kular, N. Leyland, H. Reynolds, G. Pastori, F. Wellburn, N. Baker, A. Wellburn, et al. Elevated Glutathione Biosynthetic Capacity in the Chloroplasts of Transgenic Tobacco Plants Paradoxically Causes Increased Oxidative Stress PLANT CELL, July 1, 1999; 11(7): 1277 - 1292. [Abstract] [Full Text]