title: Proteinases in excretory-secretory products of Toxocara canis second-stage larvae: zymography and modeling insights.
abstract: Components released in excretory-secretory products of Toxocara canis larvae (TES) include phosphatidylethanolamine-binding proteins (TES26), mucins (TES120, MUC2-5), and C-type lectins (TES32, TES70) and their biochemical, immunological, and diagnostic properties have been extensively studied albeit proteinase activities towards physiological substrates are almost unknown. Proteolytic activities in TES samples were first analyzed by gel electrophoresis with gelatin as substrate. Major activities of ~400, 120, and 32 kDa in TES were relatively similar over a broad pH range (5.5-9.0) and all these were of the serine-type as leupeptin abolished gelatinolysis. Further, the ~400 kDa component degraded all physiological substrates tested (laminin, fibronectin, albumin, and goat IgG) and the 120 kDa component degraded albumin and goat IgG while proteinases of lower MW (45, 32, and 26 kDa) only degraded laminin and fibronectin, preferentially at alkaline pH (9.0). By protein modeling approaches using the known sequences of TES components, only TES26 and MUC4 displayed folding patterns significantly related to reference serine proteinases. These data suggest that most of serine proteinase activities secreted in vitro by infective larvae of T. canis have intriguing nature but otherwise help the parasite to affect multiple components of somatic organs and bodily fluids within the infected host.
authors.affiliation: Departamento de Ciencias Biológicas y Programa de Posgrado en Microbiología, Facultad de Estudios Superiores Cuautitlán, Universidad Nacional Autónoma de México, 54714 Cuautitlán, MEX, Mexico.
authors.forename: Gonzalo Ernesto
authors.initials: GE
authors.lastname: González-Páez
authors.affiliation: Departamento de Ciencias Biológicas y Programa de Posgrado en Microbiología, Facultad de Estudios Superiores Cuautitlán, Universidad Nacional Autónoma de México, 54714 Cuautitlán, MEX, Mexico.
authors.forename: Fernando
authors.initials: F
authors.lastname: Alba-Hurtado
authors.affiliation: Departamento de Ciencias Biológicas y Programa de Posgrado en Microbiología, Facultad de Estudios Superiores Cuautitlán, Universidad Nacional Autónoma de México, 54714 Cuautitlán, MEX, Mexico.
authors.forename: Carlos Gerardo
authors.initials: CG
authors.lastname: García-Tovar
authors.affiliation: Departamento de Genética y Biología Molecular, Centro de Investigación y de Estudios Avanzados-IPN, 07360 Mexico City, DF, Mexico.
authors.forename: Raúl
authors.initials: R
authors.lastname: Argüello-García
mesh_terms: D000818:Animals; D000947:Antigens, Helminth / Q000737:chemistry* / Q000378:metabolism*; D003720:Densitometry; D004591:Electrophoresis, Polyacrylamide Gel; D015801:Helminth Proteins / Q000737:chemistry* / Q000378:metabolism*; D007814:Larva / Q000201:enzymology; D008958:Models, Molecular; D010447:Peptide Hydrolases / Q000737:chemistry* / Q000378:metabolism*; D059748:Proteolysis; D013379:Substrate Specificity; D017166:Toxocara canis / Q000201:enzymology*
chemical_list: D000947:Antigens, Helminth; D015801:Helminth Proteins; C045159:TES-26 protein, Toxocara canis; D010447:Peptide Hydrolases