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Biochemical and antigenic characterization of a new dipeptidyl-peptidase isolated from Aspergillus fumigatus
Journal of Biological Chemistry
Journal Article --- Old month value: Mar 7
A novel dipeptidyl-peptidase (DPP V) was purified from the culture medium of Aspergillus fumigatus. This is the first report of a secreted dipeptidyl-peptidase. The enzyme had a molecular mass of 88 kDa and contained approximately 9 kDa of N-linked carbohydrate. The expression and secretion of dipeptidyl-peptidase varied with the growth conditions; maximal intra- and extracellular levels were detected when the culture medium contained only proteins or protein hydrolysates in the absence of sugars. The gene of DPP V was cloned and showed significant sequence homology to other eukaryotic dipeptidyl-peptidase genes. Unlike the other dipeptidyl-peptidases, which are all intracellular, DPP V contained a signal peptide. Like the genes of other dipeptidyl-peptidases, that of DPP V displayed the consensus sequences of the catalytic site of the nonclassical serine proteases. The biochemical properties of native and recombinant DPP V obtained in Pichia pastoris were unique and were characterized by a substrate specificity limited to the hydrolysis of X-Ala, His-Ser, and Ser-Tyr dipeptides at a neutral pH optimum. In addition, we showed that DPP V is identical to one of the two major antigens used for the diagnosis of aspergillosis.
Amino Acid Sequence Antigens, Fungal/*chemistry Aspergillus fumigatus/*enzymology/immunology Cloning, Molecular Dipeptidyl Peptidases/antagonists & inhibitors/*chemistry/immunology Genes, Fungal Glycoproteins/chemistry Molecular Sequence Data Molecular Weight Peptide Mapping Sequence Homology, Amino Acid Substrate Specificity
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