title: Trehalose 6-phosphate synthase from Selaginella lepidophylla: purification and properties.
abstract: A protein of 440 kDa with trehalose 6-phosphate synthase activity was purified with only one purification step by immobilized metal affinity chromatography, from fully hydrated Selaginella lepidophylla plants. The enzyme was purified 50-fold with a yield of 89% and a specific activity of 7.05 U/mg protein. This complex showed two additional aggregation states of 660 and 230 kDa. The three complexes contained 50, 67, and 115 kDa polypeptides with pI of 4.83, 4.69, and 4.55. The reaction was highly specific for glucose 6-phosphate and UDP-glucose. The optimum pH was 7.0 and the enzyme was stable from pH 5.0 to 10. The enzyme was activated by low concentrations of Ca2+, Mg2+, K+, and Na+ and by fructose 6-phosphate, fructose, and glucose. Proline had an inhibitory effect, while sucrose and trehalose up to 0.4M did not have any effect on the activity. Neither the substrates nor final product had an inhibitory effect.
authors.affiliation: Dirección de Ciencia de los Alimentos, Centro de Investigación en Alimentación y Desarrollo A.C., Hermosillo, Sonora, Mexico. elisa@cascabel.ciad.mx
authors.forename: Elisa M
authors.initials: EM
authors.lastname: Valenzuela-Soto
authors.forename: Jorge A
authors.initials: JA
authors.lastname: Márquez-Escalante
authors.forename: Gabriel
authors.initials: G
authors.lastname: Iturriaga
authors.forename: Ciria G
authors.initials: CG
authors.lastname: Figueroa-Soto
mesh_terms: D050260:Carbohydrate Metabolism; D002241:Carbohydrates / Q000737:chemistry / Q000494:pharmacology; D015180:Electrophoresis, Gel, Two-Dimensional; D005964:Glucosyltransferases / Q000302:isolation & purification* / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D007477:Ions / Q000494:pharmacology; D009997:Osmotic Pressure; D032503:Selaginellaceae / Q000201:enzymology*; D013379:Substrate Specificity
chemical_list: D002241:Carbohydrates; D007477:Ions; D005964:Glucosyltransferases; C023180:trehalose-6-phosphate synthase