Differential behaviour of four plant polysaccharide synthases in the presence of organic solvents.
The behaviour of four membrane-bound glycosyl transferases involved in cell wall polysaccharide synthesis has been studied in relation to the effects of a graded series of organic solvents on their activity and type of product formed. Relative enzyme inhibition observed for some solvents was in direct relationship to the hydrophilicity of the product. This was in the order of arabinan synthase > callose synthase> xylan synthase > beta-1,4-glucan synthase. The former two were always inhibited, the xylan synthase rather less so. However, the beta-1,4-glucan synthase showed significant increases in substrate incorporation in the presence of solvents. A graded series of primary alcohols were much more effective in enhancing activity than acetone, ethyl acetate and dimethyl formamide. In the presence of the most effective solvent, methanol, there was considerable activation of beta-1,4-glucan production. This reciprocal nature of the behaviour of the beta-1,4- and beta-1,3-glucan synthases in organic solvent is supportive of recent molecular data that the two types of glucans are catalysed by separate enzyme systems. However, the results reported here do not totally negate the proposition that either enzyme is capable of synthesising the other linkage in minor amounts in vitro.
Kerry
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ME
Division of Biochemistry, School of Biological Sciences, Royal Holloway, University of London, Egham, Surrey TW20 0EX, UK.
Gregory
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AC
Bolwell
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GP
D029681:Arabidopsis Proteins; D005964:Glucosyltransferases / Q000378:metabolism*; D008565:Membrane Proteins; D009930:Organic Chemicals / Q000737:chemistry*; D010430:Pentosyltransferases / Q000378:metabolism*; D010944:Plants / Q000201:enzymology*; D029702:Schizosaccharomyces pombe Proteins; D012997:Solvents / Q000737:chemistry*
D029681:Arabidopsis Proteins; D008565:Membrane Proteins; D009930:Organic Chemicals; D029702:Schizosaccharomyces pombe Proteins; D012997:Solvents; D005964:Glucosyltransferases; C457769:PRC1 protein, Arabidopsis; C028634:cellulose synthase (UDP-forming); C020570:1,3-beta-glucan synthase; D010430:Pentosyltransferases; C038332:arabinan synthase; C038331:1,4-beta-D-xylan synthase