Improvement in isolation and identification of food-derived peptides in human plasma based on precolumn derivatization of peptides with phenyl isothiocyanate.
For the isolation and detection of food-derived peptides in blood, an approach based on the derivatization of peptides with phenyl isothiocyanate (PITC) was developed. This approach allows hydrophilic peptides to be resolved and specifically detected by reversed-phase (RP) HPLC. For the rapid capturing and clarification of peptides in human plasma, solid-phase extraction by using a mini spin column (5 mmx5 mm) packed with a strong cation exchanger was used. The clarified peptide fraction was further fractionated by size-exclusion chromatography (SEC). The peptides in the SEC fractions were derivatized with PITC, and the derivatives were resolved by RP-HPLC by using an ammonium acetate buffer or a trifluoroacetic acid system. An automatic peptide sequencer based on Edman degradation with a modified program can directly analyze the resolved derivatives. Some synthetic peptides and food-derived peptides in human plasma were successfully isolated and identified by this approach.
Aito-Inoue
Misako
M
Department of Food Sciences and Nutritional Health, Kyoto Prefectural University, Shimogamo, Kyoto 606-8522, Japan.
Ohtsuki
Kozo
K
Nakamura
Yasushi
Y
Park
Eun Young
EY
Iwai
Koji
K
Morimatsu
Fumiki
F
Sato
Kenji
K
D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D004044:Dietary Proteins / Q000097:blood*; D005502:Food; D007202:Indicators and Reagents; D017879:Isothiocyanates; D010455:Peptides / Q000097:blood*; D013861:Thiocyanates
D004044:Dietary Proteins; D007202:Indicators and Reagents; D017879:Isothiocyanates; D010455:Peptides; D013861:Thiocyanates; C005441:phenylisothiocyanate