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Sucrase‐α‐dextrinase in the spontaneously diabetic BioBreed Wistar rat: Altered intracellular carbohydrate processing
Author(s) -
Najjar Sonia M.,
Broyart JeanPierre,
Hampp Lydia T.,
Gray Gary M.
Publication year - 2001
Publication title -
journal of cellular biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.028
H-Index - 165
eISSN - 1097-4644
pISSN - 0730-2312
DOI - 10.1002/1097-4644(20010501)81:2<252::aid-jcb1040>3.0.co;2-x
Subject(s) - enterocyte , intracellular , sucrase , golgi apparatus , brush border , glycosylation , chemistry , medicine , endocrinology , biochemistry , microbiology and biotechnology , endoplasmic reticulum , biology , membrane , enzyme , small intestine , vesicle
Sucrase‐α‐dextrinase (S‐D), a glycoprotein hydrolase in the border surface of the enterocyte, is altered in congenitally diabetic BioBreed Wistar (BB d ) rats. Its intracellular assembly was examined in the current studies. Following pulse‐chase experiments, S–D was specifically immuno‐isolated from ER‐Golgi and brush border membranes, and examined by SDS‐PAGE and autoradiography. While synthesis and co‐translational glycosylation of an immature species, P i , in the ER proceeded normally, post‐translational maturation of the N‐linked carbohydrate chains was altered in the BB d rat. The mature species, P m , was 10 kDa larger in BB d than in normal rats, and ∼25% of its N‐linked chains remained immature. The difference in mass was attributed to an appreciably larger mass of the O‐linked chains of P m in BB d rats. In vivo kinetics of intracellular assembly displayed a delay in the appearance of P m in Golgi (Wistar, 15 min; BB d , 30–60 min). These experiments, revealing structural alterations in congenital diabetes suggest an important role for intracellular glycosylation in the orderly assembly and processing of brush border S‐D in the enterocyte. J. Cell. Biochem. 80:252–261, 2001. © 2001 Wiley‐Liss, Inc.