title: A new method for accurately measuring Delta(1)-pyrroline-5-carboxylate synthetase activity.
abstract: Proline is a key factor in plant adaptation to environmental stresses. The Delta(1)-pyrroline-5-carboxylate synthetase catalyzes the first committed step and the rate-limiting step for proline biosynthesis in both plants and mammals. This enzyme catalyzes the reduction of glutamate to pyrroline-5-carboxylate in two sequential steps including the phosphorylation and the reduction of its precursor. Several methods were established to assay P5CS activity but however none of them are fully reliable. Therefore, we developed a new simple and reliable assay which is based on the quantification of Pi. This assay allowed us to determine the optimal pH, the apparent K(m) and V(m) of P5CS with regard to ATP and glutamate.
authors.affiliation: Université Pierre et Marie Curie-Paris6, CNRS, PCMP, Paris, France.
authors.forename: Elodie
authors.initials: E
authors.lastname: Parre
authors.forename: Jacques
authors.initials: J
authors.lastname: de Virville
authors.forename: Françoise
authors.initials: F
authors.lastname: Cochet
authors.forename: Anne-Sophie
authors.initials: AS
authors.lastname: Leprince
authors.forename: Luc
authors.initials: L
authors.lastname: Richard
authors.forename: Delphine
authors.initials: D
authors.lastname: Lefebvre-De Vos
authors.forename: Mohamed Ali
authors.initials: MA
authors.lastname: Ghars
authors.forename: Marianne
authors.initials: M
authors.lastname: Bordenave
authors.forename: Alain
authors.initials: A
authors.lastname: Zachowski
authors.forename: Arnould
authors.initials: A
authors.lastname: Savouré
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D017360:Arabidopsis / Q000201:enzymology*; D057075:Enzyme Assays / Q000379:methods*; D018698:Glutamic Acid / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000378:metabolism*; D010936:Plant Extracts / Q000378:metabolism; D018515:Plant Leaves / Q000201:enzymology; D012995:Solubility; D013379:Substrate Specificity
chemical_list: D010936:Plant Extracts; D018698:Glutamic Acid; D000255:Adenosine Triphosphate; D017853:Phosphotransferases (Alcohol Group Acceptor)