[biobelle]

Hi all,
I hope someone can help. I have a soy hydrolysate protein which i've analysed using SELDI-ToF-MS. From this i've selected a peptide of interest which is approximately 1400 Da in molecular weight. However, this peptide makes up only a very small % of the total protein and therefore almost impossible to detect using other methods. I've sequenced the peptide and have developed a monoclonal antibody selective to the peptide (I think) however, because the peptide is of such a low concentration i can't detect it when i analyze the protein using ELISA (I need to!).
Has anyone any ideas how to concentrate the peptide enough for detection or ideally selectively separate the peptide from the protein to aid detection and then concentrate the peptide to give my antibody a better chance of detecting it. I've already tried freeze-drying my sample which isn't enough, i've also tried SPE columns to no avail as well as a few other things. The concentration needs to be extreme!!!
i hope i've made sense and that someone can *delete me*