Characterisation of selenium compounds in rye seedling biomass using 75Se-labelling/SDS-PAGE separation/gamma-scintillation counting, and HPLC-ICP-MS analysis of a range of enzymatic digests.
In the present study, selenium-enriched plant biomass was investigated to evaluate the ability of rye seedlings to take up, and assimilate, inorganic selenium. Two different analytical approaches were used. Electrophoretic separation (SDS-PAGE) of proteins extracted from 75Se-labelled biomass was used to investigate the biotransformation of selenite into organic forms of the element. Ion-pair chromatography coupled with ICP-MS detection was chosen for the analysis of selenium species, enzymatically extracted from the plant biomass. The results of three enzymatic hydrolysis procedures and three sequential enzymatic extractions procedures are compared. The most effective single extraction was proteolysis (using protease type XIV), giving an overall extraction efficiency of 48%. However, for combinations of enzymes, the most effective was cellulase (Trichoderma viride) followed by sequential extraction of the solid pellet using protease type XIV, giving an extraction efficiency of 70%. The complementary data from the electrophoretic fractionation of proteins, and the HPLC separation of Se-species in the proteolytic digests, reveal the existence of large number of selenium-containing compounds in the rye seedling plant biomass. The results showed the complete biotransformation of inorganic selenium into organic forms during germination of the rye seedlings. HPLC-ICP-MS analysis of extracts from the plant biomass did not show the presence of selenate or selenite. At the time of this study, the lack of suitable organic-MS facilities meant that it was not possible to characterise them fully. However, the data does show that a combination of different enzymes, rather than just the commonly-used protease, should be considered when developing an extraction strategy for selenium in different food types to those already reported in the literature.
Bryszewska
Malgorzata A
MA
Institute of General Food Chemistry, Technical University of Łódź, Stefanowskiego 4/10, 90-924, Łódź, Poland. malbrysz@snack.p.lodz.pl
Ambroziak
Wojciech
W
Rudzinski
Juliusz
J
Lewis
D John
DJ
D018533:Biomass; D001711:Biotransformation; D002480:Cellulase / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid; D004591:Electrophoresis, Polyacrylamide Gel; D005504:Food Analysis / Q000295:instrumentation / Q000379:methods* / Q000592:standards; D011402:Pronase / Q000737:chemistry; D011786:Quality Control; D012588:Scintillation Counting; D012434:Secale / Q000737:chemistry* / Q000378:metabolism; D036226:Seedlings / Q000737:chemistry / Q000378:metabolism; D012643:Selenium / Q000032:analysis* / Q000493:pharmacokinetics; D012644:Selenium Radioisotopes; D051140:Selenoproteins / Q000302:isolation & purification*; D021241:Spectrometry, Mass, Electrospray Ionization
D012644:Selenium Radioisotopes; D051140:Selenoproteins; D002480:Cellulase; D011402:Pronase; D012643:Selenium