title: Ping-pong character of nasturtium-seed xyloglucan endotransglycosylase (XET) reaction.
abstract: Plant xyloglucan endotransglycosylase (XET, EC 2.4.1.207) degrades its substrate by a transglycosylation mechanism while endo-cleaving xyloglucan (XG) molecules at their beta-1,4-linked polyglucosyl main chain and transferring the newly generated reducing chain ends to hydroxyls at C-4 of non-reducing glucosyl ends of the main chains of other XG molecules or of low-Mr XG-fragments (OS). Kinetic data obtained with purified nasturtium seed (Tropaeolum majus, L.) XET while using high-Mr xyloglucan and 3H-labeled XGOS alditols (DP 7-9) as substrates could be best fitted to the model for Ping-Pong Bi Bi reaction mechanism. Such mechanism is typical for transglycosylases operating with retention of the anomeric configuration of the formed glycosidic bond and involving the formation of a covalent glycosyl-enzyme reaction intermediate.
authors: Institute of Chemistry, Slovak Academy of Sciences, Bratislava.
authors: R
authors: R
authors: Baran
authors: Z
authors: Z
authors: Sulová
authors: E
authors: E
authors: Stratilová
authors: V
authors: V
authors: Farkas
mesh_terms: D016695:Glycosyltransferases / Q000378:metabolism*; D007700:Kinetics; D008962:Models, Theoretical; D019685:Rosales / Q000201:enzymology*; D012639:Seeds / Q000201:enzymology*
chemical_list: D016695:Glycosyltransferases; C073693:xyloglucan endotransglycosylase