Articulo
Two new cysteine endopeptidases obtained from the latex of Araujia hortorum fruits
Registro en:
issn:0277-8033
issn:1573-4943
Autor
Obregón, Walter David
Arribére, María Cecilia
Morcelle del Valle, Susana Raquel
Liggieri, Constanza Silvina
Caffini, Néstor Oscar
Priolo de Lufrano, Nora Silvia
Institución
Resumen
Two new endopeptidases were purified to homogeneity from the latex of Araujia hortorum fruits by a simple purification procedure involving ultracentrifugation and ion exchange chromatography. Molecular weights of araujiain h II and araujiain h III were 23,718 and 23546 (mass spectrometry), respectively. The isoelectric point of araujiain h II was 8.9, whereas araujiain h III had a pI higher than 9.3. Maximum proteolytic activity on caseine was reached at pH 8.0-9.0 for both endopeptidases, which were irreversibly inhibited by iodoacetate and E-64, suggesting they belong to the cysteine protease family. Esterolytic activity was determined on N-alpha-CBZ-amino acid-p-nitrophenyl esters, and the highest kcat/Km values for the both enzymes were obtained with the glutamine derivative. The N-terminal sequences of araujiain h II and araujiain h III showed a high degree of homology with other plant cysteine endopeptidases. Centro de Investigación de Proteínas Vegetales