Abstract
Dipeptidyl peptidases 8 and 9 have been identified as gene members of the S9b family of dipeptidyl peptidases. In the present paper, we report the characterization of recombinant dipeptidyl peptidases 8 and 9 using the baculovirus expression system. We have found that only the full-length variants of the two proteins can be expressed as active peptidases, which are 882 and 892 amino acids in length for dipeptidyl peptidase 8 and 9 respectively. We show further that the purified proteins are active dimers and that they show similar Michaelis-Menten kinetics and substrate specificity. Both cleave the peptide hormones glucagon-like peptide-1, glucagon-like peptide-2, neuropeptide Y and peptide YY with marked kinetic differences compared with dipeptidyl peptidase IV. Inhibition of dipeptidyl peptidases IV, 8 and 9 using the well-known dipeptidyl peptidase IV inhibitor valine pyrrolidide resulted in similar K(i) values, indicating that this inhibitor is non-selective for any of the three dipeptidyl peptidases.
MeSH terms
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Amino Acid Sequence
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Baculoviridae / genetics
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Baculoviridae / metabolism
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Chromatography, Gel
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Dipeptidases / chemistry*
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Dipeptidases / genetics
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Dipeptidases / isolation & purification
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Dipeptidases / metabolism
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Dipeptidyl Peptidase 4 / chemistry*
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Dipeptidyl Peptidase 4 / metabolism
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Dipeptidyl-Peptidases and Tripeptidyl-Peptidases / chemistry*
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Dipeptidyl-Peptidases and Tripeptidyl-Peptidases / genetics
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Dipeptidyl-Peptidases and Tripeptidyl-Peptidases / isolation & purification
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Dipeptidyl-Peptidases and Tripeptidyl-Peptidases / metabolism
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Enzyme Activation
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Enzyme Inhibitors / metabolism
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Enzyme Inhibitors / pharmacology
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Humans
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Kinetics
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Molecular Sequence Data
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Peptide Fragments / chemistry
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Peptide Fragments / metabolism
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Protein Structure, Quaternary
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Pyrroles / metabolism
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Pyrroles / pharmacology
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Recombinant Proteins / genetics
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Recombinant Proteins / isolation & purification
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Recombinant Proteins / metabolism
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Sequence Alignment
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Substrate Specificity
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Valine / metabolism
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Valine / pharmacology
Substances
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Enzyme Inhibitors
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Peptide Fragments
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Pyrroles
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Recombinant Proteins
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valine-pyrrolidide
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Dipeptidases
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DPP9 protein, human
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Dipeptidyl-Peptidases and Tripeptidyl-Peptidases
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DPP8 protein, human
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Dipeptidyl Peptidase 4
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Valine