Tryptic hydrolysis of bovine alpha(S2)-casein: identification and release kinetics of peptides

Bovine alpha(S2)-casein was purified by anionic exchange and hydrophobic interaction chromatographies. The purified alpha(S2)-casein was hydrolysed with trypsin; the resulting peptides were identified by amino acids composition and on line reversed-phase high performance liquid chromatography coupled with electrospray mass spectrometry. A study on the kinetics of peptide release enabled discrimination between different protein areas according to their surface-accessibility. Data from the kinetic study were reconciled with secondary structure predictions and a hypothetical model of the structural organisation of purified bovine alpha(S2)-casein in solution was proposed. (C) 2003 Elsevier Science Ltd. All rights reserved.