Glucose polyester biosynthesis. Purification and characterization of a glucose acyltransferase

• Published in: Plant physiology (Bethesda) 1999-10, Vol.121 (2), p.453-460
• Main Authors: Li, A.X, Eannetta, N, Ghangas, G.S, Steffens, J.C
• Format: Article
• Language: English
• Subjects: Acetates - metabolism; acyltransferases; Acyltransferases - chemistry; Acyltransferases - isolation & purification; Acyltransferases - metabolism; Amino Acid Sequence; amino acid sequences; Biochemistry and Macromolecular Structure; Biological and medical sciences; Biosynthesis; carbohydrate metabolism; Chromatography; Chromatography, Affinity; Chromatography, Ion Exchange; Electrophoresis, Polyacrylamide Gel; enzyme activity; Enzymes; Esters; Fatty acids; Fractionation; Fundamental and applied biological sciences. Psychology; Gels; glucose; Glucose - analogs & derivatives; Indicators and Reagents; isoelectric point; Kinetics; Lycopersicon esculentum - enzymology; Metabolism; Metabolism. Physicochemical requirements; Molecular Sequence Data; molecular weight; Peptide Fragments - chemistry; Peptide Fragments - isolation & purification; pest resistance; plant glands; Plant physiology and development; Plants; Polyesters; Proteins; secretion; secretions; Solanum pennellii var. pennellii; substrates; Tomatoes; Trichomes
• ISSN: 0032-0889; 1532-2548
• DOI: 10.1104/pp.121.2.453

Glandular trichomes of the wild tomato species Lycopersicon pennellii secrete 2,3,4-O-tri-acyl-glucose (-Glc), which contributes to insect resistance. A Glc acyltransferase catalyzes the formation of diacyl-Glc by disproportionating two equivalents of 1-O-acyl-beta-Glc, a high-energy molecule formed by a UDP-Glc dependent reaction. The acyltransferase was purified 4,900-fold from L. pennellii leaves by polyethylene glycol fractionation, diethylaminoethyl chromatography, concanavalin A affinity chromatography, and chromatofocusing. The acyltransferase possesses an isoelectric point of 4.8, a relative molecular mass around 110 kD, and is composed of 34- and 24-kD polypeptides as a heterotetramer. The 34- and 24-kD proteins were partially sequenced. The purified enzyme catalyzes both the disproportionation of 1-O-acyl-beta-Glcs to generate 1,2-di-O-acyl-beta-Glc and anomeric acyl exchange between 1-O-acyl-beta-Glc and Glc.