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developer of the AIDS-HIV Reference project
Abstract No.: MoP-LB5
Session: LATE-BREAKING/Food and Nutrition
Presentation date: Mon, Aug 28, 2006
Presentation time: 09:50 – 11:20

Quantification of ACE-Inhibiting Peptides in Human Plasma

Chris van Platerink1, Christian Grun1, Hans-Gerd Janssen1

1 Unilever Food and Health Research Institute, Vlaardingen, Netherlands

Correspondence address: Christian Grun, Unilever Food and Health Research Institute, Advanced Measurement and Imaging, Olivier van Noortlaan 120, Vlaardingen, 3133 AT Netherlands.

Keywords: Peptide; Plasma, Human; Quadrupole, Triple; Quantitative Analysis.

Novel aspect: Rapid and very sensitive method for the quantification of peptides in human plasma


An HPLC-MRM–MS method was developed for the quantification of 17 small ACE-inhibiting (ACEI) peptides in plasma samples collected from human volunteers after the consumption of a peptide-enriched drink, developed to effect lowering of the blood pressure. The assay shows the high selectivity and sensitivity necessary to monitor small changes in the levels of the ACEI peptides after consumption of the drinks. A number of sample preparation methods were evaluated in order to obtain optimal recovery of the peptides of interest. In our hands, acid- and heat-induced protein precipitation followed by large volume injection of the supernatant proved to be the best method for full peptide coverage and maximum sensitivity. The isotope-labeled form of one of the peptides of interest, [U13C]IPP, was used as an internal standard. The limit of detection of the assay is below 0.01 ng/ml. The limit of quantification is between 0.05 and 0.2 ng/ml, which is approximately 10% of the expected peptide concentration in plasma based on a normal diet. The intra- and inter-day relative standard deviations for all peptides were shown to be below 25% and the method has an accuracy of better than 75%. The assay has been successfully applied to blood samples collected from volunteers during a human trial.