Detection and characterization by high-performance liquid chromatography and mass spectrometry of two truncated goat alphas2-caseins

Rapid Commun Mass Spectrom. 2006;20(7):1061-70. doi: 10.1002/rcm.2415.

Abstract

The identification and characterization of truncated forms of goat alphas2-Cn variants A and E are reported. The two proteins, which have experimental Mr values of 24 183 and 24 227 Da, were detected as minor components in a goat milk sample from an autochthonous breed of southern Italy, 'Rossa Mediterranea', by reversed-phase high-performance liquid chromatography/electrospray ionization mass spectrometry (RP-HPLC/ESI-MS). Characterization of the amino acid sequences, performed by coupling trypsin digestion with matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS), RP-HPLC/ESI-MS and tandem mass spectrometry (MS/MS), demonstrated that the polypeptide chains correspond to the 1-204 sequence of mature alphas2-Cn variant A (component with Mr of 24 183 Da) and E (component with Mr of 24 227 Da), respectively. These components seem to be the product of a differential splicing of pre-messenger RNA during the translation process of the alphas2-Cn variants A and E.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Caseins / analysis*
  • Caseins / chemistry*
  • Chromatography, High Pressure Liquid / methods*
  • Goats
  • Milk / chemistry*
  • Molecular Sequence Data
  • Molecular Weight
  • Peptide Mapping / methods*
  • Spectrometry, Mass, Electrospray Ionization / methods*

Substances

  • Caseins