Study of the enzymatic degradation of vasostatin I and II and their precursor chromogranin A by dipeptidyl peptidase IV using high-performance liquid chromatography/electrospray mass spectrometry

✍ Scribed by Zhang, X. Y.; De Meester, I.; Lambeir, A.-M.; Dillen, L.; Van Dongen, W.; Esmans, E. L.; Haemers, A.; Scharpé, S.; Claeys, M.

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 167 KB
• Volume: 34
• Category: Article
• ISSN: 1076-5174
• DOI: 10.1002/(sici)1096-9888(199904)34:4<255::aid-jms752>3.0.co;2-7

✦ Synopsis

The interaction of dipeptidyl peptidase IV with structurally related proteins di †ering in chain length, namely vasostatin I and II and their precursor protein chromogranin A, was examined using high-performance liquid chromatography in combination with electrospray mass spectrometry. Suitable analytical procedures were developed involving the use of reversed-phase high-performance liquid chromatography for puriÐcation of the enzymatic degradation products and a peptide mapping procedure for evaluating the enzymatic degradation of the large precursor protein chromogranin A. While vasostatin I was found to be a substrate for dipeptidyl peptidase IV, no N-terminal cleavage of Leu-Pro could be noted for chromogranin A. With respect to vasostatin II, N-terminal degradation was only observed after degradation in the C-terminal domain to proteins containing O78 amino acids. The speciÐcity of the N-terminal release of Leu-Pro was proved by addition of a DPP IV speciÐc inhibitor.