title: Determination of S-adenosyl-l-methionine in fruits by capillary electrophoresis.
abstract: BACKGROUND
  S-adenosyl-l-methionine (SAM) plays an important role in many biochemical reactions in plants. It is mainly used as a methyl donor for methylation reactions, but it also participates in, for example, the biosynthesis of polyamines and the plant hormone ethylene.
  
  
  OBJECTIVE
  To develop a fast capillary electrophoresis technique to separate SAM in fruits and fruit juices without any pre-purification steps.
  
  
  METHODS
  Four different extraction solutions and two extraction times were tested, of which 5% trichloroacetic acid (TCA) for 10 min was found most suited. A glycine : phosphate buffer (200 : 50 mm, pH 2.5) was found optimal to analyse SAM in TCA extracts. Analyses were preformed on different climacteric and non-climacteric fruits and fruit juices. The calibration curve was created in degraded tomato extract. The CE-method was compared with a more conventional HPLC method described in literature.
  
  
  RESULTS
  The CE technique made it possible to completely separate the S,S- and R,S-diastereoisomeric forms of SAM. The CE method proved to be very fast (20 min total running time instead of 42 min) and more sensitive (limit of detection of 0.5 µm instead of 1 µm) compared with the conventional HPLC method.
  
  
  CONCLUSIONS
  Fast measurements of SAM in fruits and juices are favoured by capillary electrophoresis in a 200 : 50 mm glycine : phosphate (pH 2.5) buffer system.
authors.affiliation: Department of Biosystems, Katholieke Universiteit Leuven, Willem de Croylaan 42, Leuven, Belgium. bram.vandepoel@biw.kuleuven.be
authors.forename: Bram
authors.initials: B
authors.lastname: Van de Poel
authors.forename: Inge
authors.initials: I
authors.lastname: Bulens
authors.forename: Pieter
authors.initials: P
authors.lastname: Lagrain
authors.forename: Jeroen
authors.initials: J
authors.lastname: Pollet
authors.forename: Maarten L A T M
authors.initials: ML
authors.lastname: Hertog
authors.forename: Jeroen
authors.initials: J
authors.lastname: Lammertyn
authors.forename: Maurice P
authors.initials: MP
authors.lastname: De Proft
authors.forename: Bart M
authors.initials: BM
authors.lastname: Nicolaï
authors.forename: Annemie H
authors.initials: AH
authors.lastname: Geeraerd
mesh_terms: D002021:Buffers; D002138:Calibration; D002851:Chromatography, High Pressure Liquid; D019075:Electrophoresis, Capillary; D005638:Fruit / Q000737:chemistry*; D007202:Indicators and Reagents; D018551:Solanum lycopersicum / Q000737:chemistry; D010936:Plant Extracts / Q000032:analysis; D012436:S-Adenosylmethionine / Q000032:analysis* / Q000302:isolation & purification; D012996:Solutions; D013237:Stereoisomerism
chemical_list: D002021:Buffers; D007202:Indicators and Reagents; D010936:Plant Extracts; D012996:Solutions; D012436:S-Adenosylmethionine