Alterations of glycosidases in human colonic adenocarcinoma
1997; Elsevier BV; Volume: 30; Issue: 1 Linguagem: Inglês
10.1016/s0009-9120(96)00123-3
ISSN1873-2933
AutoresEmilio Gil‐Martín, Javier Rodríguez-Berrocal, Marı́a Páez de la Cadena, Almudena Fernández‐Briera,
Tópico(s)Enzyme Production and Characterization
ResumoObjectives: We have carried out a detailed study of some glycosidases in an attempt to explain the differential profile of enzyme activity between human colonic adenocarcinoma and normal mucosa. Design and Methods: Several glycosidase activities associated with human colonic adenocarcinoma and control tissues were submitted to a detailed structural and functional characterization. Results: Tumoral and control samples were assayed for β-d-galactosidase, β-d-glucuronidase, α-d-mannosidase, β-NAc-d-glucosaminidase and β-NAc-d-galactosaminidase activities. Tumoral tissue showed higher β-d-galactosidase, β-NAc-d-glucosaminidase, and β-NAc-d-galactosaminidase activities than control tissue. Glycosidases from tumoral and control tissues demonstrated no differences in optimum pH, subcellular distribution, pH and thermal stability. However, the kinetic analysis showed a statistically significant increased Vmax in tumoral colon with respect to the control for β-d-galactosidase, β-NAc-d-glucosaminidase, and β-NAc-d-galactosaminidase activities. The Km remained unaltered. Conclusions: The increased Vmax detected for some glycosidase activities in human colonic adenocarcinoma could correspond with a greater presence of enzyme proteins in the tumoral cells, and not to changes in protein and/or active site structure.
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