Table I

Enrichment of phosphopeptides derived from standard proteins

Tryptic digests of α-casein, fetuin, and phosvitin (started from 2.5 μg of each protein) were purified using MOC tips with/without hydroxy acids, and the eluted fractions were analyzed by means of nano-LC-MS/MS with QSTAR and Mascot search.

MOC modifierIdentified peptides (p < 0.05)
No. of phosphopeptidesNo. of non-phosphopeptides
Titania
    None810
    DHB43
    Glycolic acid1011
    Lactic acid120
    Malic acid60
    Tartaric acid82
    HPA60
Zirconia
    None913
    DHB33
    Glycolic acid84
    Lactic acid101
    Malic acid60
    Tartaric acid53
    HPA110
Alumina
    None117
    DHB02
    Glycolic acid01
    Lactic acid04
    Malic acid14
    HPA13
Al(OH)3·xH2O
    None817
    DHB48
    Glycolic acid03
    Lactic acid04
    Malic acid05
    HPA07
Boehmite
    None011
    DHB06
    Glycolic acid18
    Lactic acid07
    Malic acid012
    HPA010