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 (43) Citing Articles via Google Scholar Google Scholar Articles by Henry, R. J. Articles by Stone, B. A. Search for Related Content PubMed PubMed Citation Articles by Henry, R. J. Articles by Stone, B. A. Agricola Articles by Henry, R. J. Articles by Stone, B. A.

Articles

Factors Influencing -Glucan Synthesis by Particulate Enzymes from Suspension-Cultured Lolium multiflorum Endosperm Cells ¹

Department of Biochemistry, La Trobe University, Bundoora, Victoria 3083, Australia

Particulate enzymes from suspension-cultured ryegrass (Lolium multiflorum Lam.) endosperm cells incorporated glucosyl residues from UDP-glucose and GDP-glucose into -glucans. Three types of -glucans were produced from UDP-glucose: 1,3--glucan; 1,4--glucan; and mixed-linkage 1,3;1,4--glucan. As in other systems, relatively more 1,4--glucan was produced from a low (10 micromolar) UDP-glucose concentration, and relatively more 1,3--glucan was produced from a high (1 millimolar) UDP-glucose concentration. However, in ryegrass, 1,3;1,4--glucan represented a major proportion of the products at both low and high UDP-glucose concentrations. The arrangement of linkages in the 1,3;1,4--glucan was different at the two concentrations; at the low UDP-glucose concentration, more sequences of three consecutive 1,4-linkages were produced.

The effects of pH, temperature, and metal ion concentrations on incorporation were dependent on the UDP-glucose concentration. At the low UDP-glucose concentration, incorporation into all three types of -glucan increased with increasing pH. At the high UDP-glucose concentration, 1,3--glucan was the major product at pH 7 and below; 1,4--glucan synthesis was optimal at pH 8; and synthesis of 1,3;1,4--glucan was greatest above pH 8.

With 10 micromolar GDP-glucose as substrate, 1,4--glucan, but no 1,3;1,4--glucan, was produced. Incorporation from either UDP-glucose or GDP-glucose was not influenced by the presence of the other.

This article has been cited by other articles:

				M. S. Buckeridge, C. E. Vergara, and N. C. Carpita The Mechanism of Synthesis of a Mixed-Linkage (1right-arrow3),(1right-arrow4)beta -D-Glucan in Maize. Evidence for Multiple Sites of Glucosyl Transfer in the Synthase Complex Plant Physiology, August 1, 1999; 120(4): 1105 - 1116. [Abstract] [Full Text]