title: The proteolytic activities in latex from Carica candamarcensis.
abstract: Prior evidence suggests that proteinases in latex from Caricaceae protect against injuries induced by physical wounding. While the proteolytic enzymes from Carica papaya are well characterized, the homologues from Carica candamarcensis were not given similar attention, probably because its distribution is restricted to South American regions. We describe the chromatographic steps to fractionate 14 components from C. candamarcensis, 12 of them displaying amidase activity. The mass of these proteins plus two others isolated by HPLC rank between 23,943 and 22,991Da, and their N-terminal sequences showed similarities or identities with the enzymes described earlier in this species. Following CM-Sephadex chromatography two major peaks containing proteolytic activity were resolved. Each of these peaks was further resolved by Mono S chromatography yielding several purified fractions. The kinetic parameters of two of the Mono S purified enzymes originated from each of the CMS-Sephadex peaks were determined. While the Km with (Pyr-Phe-Leu-pNA), is similar in both enzymes, the kcat for one of them is 10-fold lower than the other. Based on these differences it is proposed that two groups of proteinases exist in latex of C. candamarcensis.
authors.affiliation: Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, UFMG, 31270-901 Belo Horizonte, MG, Brasil.
authors.forename: Raphael D
authors.initials: RD
authors.lastname: Teixeira
authors.forename: Henrique A L
authors.initials: HA
authors.lastname: Ribeiro
authors.forename: Marco-Túlio R
authors.initials: MT
authors.lastname: Gomes
authors.forename: Miriam T P
authors.initials: MT
authors.lastname: Lopes
authors.forename: Carlos E
authors.initials: CE
authors.lastname: Salas
mesh_terms: D029441:Carica / Q000201:enzymology*; D002845:Chromatography; D003546:Cysteine Endopeptidases / Q000302:isolation & purification / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D007840:Latex / Q000737:chemistry / Q000378:metabolism*; D013058:Mass Spectrometry; D010940:Plant Proteins / Q000302:isolation & purification / Q000378:metabolism*
chemical_list: D007840:Latex; D010940:Plant Proteins; D003546:Cysteine Endopeptidases