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 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 Google Scholar Google Scholar Articles by Spilatro, S. R. Articles by Preiss, J. Search for Related Content PubMed PubMed Citation Articles by Spilatro, S. R. Articles by Preiss, J. Agricola Articles by Spilatro, S. R. Articles by Preiss, J.

Metabolism and Enzymology

Regulation of Starch Synthesis in the Bundle Sheath and Mesophyll of Zea mays L. ¹

Intercellular Compartmentalization of Enzymes of Starch Metabolism and the Properties of the ADPglucose Pyrophosphorylases

Department of Biochemistry, Michigan State University, East Lansing, Michigan 48824

The intercellular localization of enzymes involved in starch metabolism and the kinetic properties of ADPglucose pyrophosphorylase were studied in mesophyll protoplasts and bundle sheath strands separated by cellulase digestion of Zea mays L. leaves. Activities of starch synthase, branching enzyme, and ADPglucose pyrophosphorylase were higher in the bundle sheath, whereas the degradative enzymes, starch phosphorylase, and amylase were more evenly distributed and slightly higher in the mesophyll. ADPglucose pyrophosphorylase partially purified from the mesophyll and bundle sheath showed similar apparent affinities for Mg²⁺, ATP, and glucose-1-phosphate. The pH optimum of the bundle sheath enzyme (7.0-7.8) was lower than that of the mesophyll enzyme (7.8-8.2). The bundle sheath enzyme showed greater activation by 3-phosphoglycerate than did the mesophyll enzyme, and also showed somewhat higher apparent affinity for 3-phosphoglycerate and lower apparent affinity for the inhibitor, orthophosphate. The observed activities of starch metabolism pathway enzymes and the allosteric properties of the ADPglucose pyrophosphorylases appear to favor the synthesis of starch in the bundle sheath while restricting it in the mesophyll.

This article has been cited by other articles:

				R. C. Leegood Roles of the bundle sheath cells in leaves of C3 plants J. Exp. Bot., May 1, 2008; 59(7): 1663 - 1673. [Abstract] [Full Text] [PDF]

				W. Majeran, Y. Cai, Q. Sun, and K. J. van Wijk Functional Differentiation of Bundle Sheath and Mesophyll Maize Chloroplasts Determined by Comparative Proteomics PLANT CELL, November 1, 2005; 17(11): 3111 - 3140. [Abstract] [Full Text] [PDF]

				E. Baroja-Fernandez, F. J. Munoz, T. Akazawa, and J. Pozueta-Romero Reappraisal of the Currently Prevailing Model of Starch Biosynthesis in Photosynthetic Tissues: A Proposal Involving the Cytosolic Production of ADP-Glucose by Sucrose Synthase and Occurrence of Cyclic Turnover of Starch in the Chloroplast Plant Cell Physiol., December 1, 2001; 42(12): 1311 - 1320. [Abstract] [Full Text] [PDF]