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.
The interaction of dipeptidyl peptidase IV with structurally related proteins differing 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 purification 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 < or = 78 amino acids. The specificity of the N-terminal release of Leu-Pro was proved by addition of a DPP IV specific inhibitor.
Zhang
X Y
XY
Department of Pharmaceutical Sciences, University of Antwerp (UIA), Belgium.
De Meester
I
I
Lambeir
A M
AM
Dillen
L
L
Van Dongen
W
W
Esmans
E L
EL
Haemers
A
A
Scharpé
S
S
Claeys
M
M
D000595:Amino Acid Sequence; D000818:Animals; D002384:Catalysis; D002417:Cattle; D002851:Chromatography, High Pressure Liquid; D053379:Chromogranin A; D002864:Chromogranins / Q000737:chemistry*; D018819:Dipeptidyl Peptidase 4 / Q000737:chemistry*; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry*
D053379:Chromogranin A; D002864:Chromogranins; D010446:Peptide Fragments; C102106:vasostatin II; D018819:Dipeptidyl Peptidase 4