Purification and Characterization of Barley Dipeptidyl Peptidase IV1
AUTOR(ES)
Davy, Anne
FONTE
American Society of Plant Physiologists
RESUMO
Barley (Hordeum vulgare L.) storage proteins, which have a high content of proline (Pro) and glutamine, are cleaved by cysteine endoproteases to yield peptides with a Pro next to the N-terminal and/or C-terminal amino acid residues. A peptidase cleaving after Xaa-Pro- at the N terminus of peptides was purified from green barley malt. It was identified as a serine-type dipeptidyl peptidase (DPP), based on inhibitor studies, and the nature of the cleavage product. It is a monomeric glycoprotein with an apparent molecular mass of 105 kD (85 kD after deglycosylation), with a pI of 3.55 and a pH optimum at 7.2. Substrate specificity was determined with a series of fluorogenic peptide substrates with the general formula Xaa-Pro-AMC, where Xaa is an unspecified amino acid and AMC is 7-amino-4-methylcoumarin. The best substrates were Xaa = lysine and arginine, while the poorest were Xaa = aspartic acid, phenylalanine, and glutamic acid. The Km values ranged from 0.071 to 8.9 μm, compared with values of 9 to 130 μm reported for mammalian DPP IVs. We discuss the possible role of DPP IV in the degradation of small Pro-containing peptides transported from the endosperm to the embryo of the germinating barley grain.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=58879Documentos Relacionados
- Emerging Family of Proline-Specific Peptidases of Porphyromonas gingivalis: Purification and Characterization of Serine Dipeptidyl Peptidase, a Structural and Functional Homologue of Mammalian Prolyl Dipeptidyl Peptidase IV
- Purification and Characterization of an X-Prolyl-Dipeptidyl Peptidase from Lactobacillus sakei
- Cloning, Purification, and Enzymatic Properties of Dipeptidyl Peptidase IV from the Swine Pathogen Streptococcus suis
- Characterization of the Prolyl Dipeptidyl Peptidase Gene (dppIV) from the Koji Mold Aspergillus oryzae
- Role of CD26/dipeptidyl peptidase IV in human immunodeficiency virus type 1 infection and apoptosis.