OBJECTIVES: 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 beta-D-galactosidase, beta-D-glucuronidase, alpha-D-mannosidase, beta-NAc-D-glucosaminidase and beta-NAc-D-galactosaminidase activities. Tumoral tissue showed higher beta-D-galactosidase, beta-NAc-D-glucosaminidase, and beta-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 beta-D-galactosidase, beta-NAc-D-glucosaminidase, and beta-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.
OBJECTIVES: We have carried out a detailed study of some glycosidases in an attempt to explain the differential profile of enzyme activity between humancolonic adenocarcinoma and normal mucosa. DESIGN AND METHODS: Several glycosidase activities associated with humancolonic adenocarcinoma and control tissues were submitted to a detailed structural and functional characterization. RESULTS:Tumoral and control samples were assayed for beta-D-galactosidase, beta-D-glucuronidase, alpha-D-mannosidase, beta-NAc-D-glucosaminidase and beta-NAc-D-galactosaminidase activities. Tumoral tissue showed higher beta-D-galactosidase, beta-NAc-D-glucosaminidase, and beta-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 beta-D-galactosidase, beta-NAc-D-glucosaminidase, and beta-NAc-D-galactosaminidase activities. The Km remained unaltered. CONCLUSIONS: The increased Vmax detected for some glycosidase activities in humancolonic 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.
Authors: Crina I A Balog; Kathrin Stavenhagen; Wesley L J Fung; Carolien A Koeleman; Liam A McDonnell; Aswin Verhoeven; Wilma E Mesker; Rob A E M Tollenaar; André M Deelder; Manfred Wuhrer Journal: Mol Cell Proteomics Date: 2012-05-09 Impact factor: 5.911