title: Phosphoenolpyruvate carboxykinase and gluconeogenesis in grape pericarp.
abstract: Glycolysis from sugars is necessary at all stages of development of grape pericarp, and this raises the question as to why gluconeogenesis from malate occurs. Phosphoenolpyruvate carboxykinase (PEPCK) is required for gluconeogenesis in grape pericarp. In this study we determined the abundance of PEPCK protein and activity in different parts of grape pericarp during its development. Both PEPCK protein and activity were present throughout development, however, in both the skin and the flesh their abundance increased greatly at the start of ripening. This coincided with the onset of the decrease in the malate content of the berry. The location of PEPCK in the pericarp at different stages of development was determined using both immunohistochemistry and dissection. We provide a possible explanation for the occurrence of gluconeogenesis in grape pericarp.
authors.affiliation: Dipartimento di Scienze Agrarie, Alimentari e Ambientali, Università degli Studi di Perugia, Borgo XX Giugno, 74, 06121, Perugia, Italy. Electronic address: rob.walker@talktalk.net.
authors.forename: Robert P
authors.initials: RP
authors.lastname: Walker
authors.affiliation: Istituto di Biologia Agroambientale e Forestale, CNR, Viale Marconi, 2, 05010, Porano (TR), Italy.
authors.forename: Alberto
authors.initials: A
authors.lastname: Battistelli
authors.affiliation: Istituto di Biologia Agroambientale e Forestale, CNR, Viale Marconi, 2, 05010, Porano (TR), Italy.
authors.forename: Stefano
authors.initials: S
authors.lastname: Moscatello
authors.affiliation: Department of Animal and Plant Sciences, University of Sheffield, Sheffield, S10 2 TN, UK.
authors.forename: László
authors.initials: L
authors.lastname: Técsi
authors.affiliation: Department of Animal and Plant Sciences, University of Sheffield, Sheffield, S10 2 TN, UK.
authors.forename: Richard C
authors.initials: RC
authors.lastname: Leegood
authors.affiliation: Dipartimento di Scienze Agrarie, Alimentari e Ambientali, Università degli Studi di Perugia, Borgo XX Giugno, 74, 06121, Perugia, Italy. Electronic address: franco.famiani@unipg.it.
authors.forename: Franco
authors.initials: F
authors.lastname: Famiani
mesh_terms: D005638:Fruit / Q000378:metabolism; D005943:Gluconeogenesis; D008293:Malates / Q000378:metabolism*; D010728:Phosphoenolpyruvate / Q000378:metabolism; D010730:Phosphoenolpyruvate Carboxylase / Q000378:metabolism*; D010940:Plant Proteins / Q000378:metabolism; D014617:Vacuoles / Q000378:metabolism; D027843:Vitis / Q000201:enzymology*
chemical_list: D008293:Malates; D010940:Plant Proteins; D010728:Phosphoenolpyruvate; C030298:malic acid; D010730:Phosphoenolpyruvate Carboxylase
keywords: Gluconeogenesis; Grape; Malate; Organic acids; Phosphoenolpyruvate carboxykinase; Vitis vinifera L.