Title
A method for assaying intestinal brush border sucrase in an intact intestinal preparation
Document Type
Article
Publication Date
1998
Publication Title
Proceedings of the National Academy of Science
Department
Biology
Abstract
Small intestinal brush-border hydrolases usually are assayed in intestinal mucosal homogenates resuspended in solutions of unphysiological ionic composition. Thus, extrapolation of measured Vmax values (maximal reaction rates at high substrate concentrations) to in vivo conditions, hence comparison with physiological substrate loads, is uncertain. We therefore have developed a sucrase assay in an intact preparation of mouse small intestine, an everted intestinal sleeve incubated in a physiological Ringer's solution. As in homogenate studies, sucrase is assayed by glucose production measured colorimetrically, but uptake of liberated glucose into the intestinal sleeve is prevented by the transport inhibitor phlorizin. The coefficient of variation of Vmax is 16% for sleeves from the same mouse and 8% for mean values from different mice. Sleeve sucrase activity is abolished by the inhibitor castanospermine. Activity in sleeves and homogenates proves to be the same when measured under identical solution conditions, but variations in assay conditions cause large activity changes from values measured in physiological solutions.
ISSN
0027-8424
WorldCat Link
Provider Link
Citation
Lee, Eric A, Stacey L. Weiss, Mandy Lam, Rosa Torres, and Jared Diamond. "A Method for Assaying Intestinal Brush-Border Sucrase in an Intact Intestinal Preparation." Proceedings of the National Academy of Sciences of the United States of America. 95.5 (1998): 2111-2116. Print.