High-performance liquid chromatography-mass spectrometry of an osteocalcinderivative

High-performance liquid chromatography (HPLC) was combined on-line with ele ctrospray ionization mass spectrometry (ESI-MS) for structural analysis of a synthetic osteocalcin derivative and its degradation products. Initial de termination of amino acid sequence of the synthetic peptide was performed a fter tryptic degradation. Hydrolytic degradation of the osteocalcin derivat ive was studied under different pH conditions: pH 2, pH 7 and pH 10 at 60 d egrees C up to 20 h. According the HPLC-ESI-MS results, the chemical stabil ity was dependent on pH. Two major degradation products and a number of oth er fragments were obtained in acidic solution, whereas the osteocalcin mole cule was rather stable in neutral and alkaline conditions. (C) 1999 Elsevie r Science B.V. All rights reserved.