Rat intestinal microvillus membrane sucrase-isomaltase is a single high molecular weight protein and fully active enzyme in the absence of luminal factors

Montgomery, Robert K.; Sybicki, Mariana A.; Forcier, Ann G.; Grand, Richard J.

doi:10.1016/0005-2744(81)90024-3

Cited by 35 publications

(10 citation statements)

References 13 publications

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“…However, the influence of these other membrane fractions of sucrase-isomaltase on our results, i.e. the decrease of sucrase activity in the lower jejunum and the increase of sucrase activity in rats with ligated pancreatic duct, is unlikely because (a) the membranes in intestinal epithelial cells, except microvillus membrane, are not exposed to luminal factors, (b) pro-(sucrase-isomaltase) in Golgi and other intracellular membranes is fully catalytically active (Hauri et al, 1979;Montgomery et al, 1981); and (c) sucrase activity is practically unaffected by lysosomal enzymes in vitro (Seetharam et al, 1976).…”

Section: Discussionmentioning

confidence: 71%

“…The dimeric enzyme sucrase-isomaltase (a complex of sucrose a-glucohydrolase, EC 3.2.1.48, and isomaltase, EC 3.2.1 .10) is synthesized as a single chain precursor protein with enzymic activity (Hauri et al, 1979(Hauri et al, , 1982Sj6strom et al, 1980;Montgomery et al, 1981). In the intestinal brush border membrane, this precursor protein is cleaved into its mature subunits by the action of pancreatic proteinases (Hauri et al, 1979;Sjostrom et al, 1980).…”

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confidence: 99%

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Evidence of degradation process of sucrase-isomaltase in jejunum of adult rats

Goda¹,

Koldovský²

1985

Biochemical Journal

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To evaluate degradation processes of sucrase-isomaltase in adult rat jejunum, we determined enzymic activity of sucrase and isomaltase and compared it with the amount of immunoreactive sucrase-isomaltase. In rats fed or starved for 18h, killed at 10:00 h or 22:00 h, sucrase activity (expressed on the basis of total protein or of immunoreactive sucrase-isomaltase) was significantly (P less than 0.02) lower in the lower jejunum than in the upper jejunum; isomaltase activity was similar in both segments. Crossed immunoelectrophoresis demonstrated the existence of a second sucrase-isomaltase antigen reacting with anti-(sucrase-isomaltase) serum. This antigen was present in larger amounts in the lower jejunum than in the upper jejunum, exhibited immunological partial identity with the intact sucrase-isomaltase, and had isomaltase activity but no sucrase activity. Results suggest that this antigen is a degradation product of sucrase-isomaltase in which the sucrase active site has been broken down. To examine the role of pancreatic enzymes in degradation of sucrase-isomaltase, common pancreatico-biliary ducts were ligated. Within 18 h after the operation, the difference of sucrase activity between the upper and the lower jejunum disappeared and the amount of the second sucrase-isomaltase antigen markedly decreased in the lower jejunum. Our results indicate that, during the degradation of intestinal sucrase-isomaltase by the pancreatic proteinases, degradation of the sucrase active site precedes that of the isomaltase active site.

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Section: Discussionmentioning

confidence: 71%

mentioning

confidence: 99%

Evidence of degradation process of sucrase-isomaltase in jejunum of adult rats

Goda¹,

Koldovský²

1985

Biochemical Journal

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“…Interestingly, we observed that the activity ratio of S to I was higher in the jejunum than in the ileum. Recently, it was demonstrated that sucrase-isomaltase complex might be converted from a large single poly peptide by the action of pancreatic proteases (19,20). Since insulin has been re ported to stimulate the protein and digestive enzyme synthesis in exocrine pan creas (21), in the case of insulin deficiency such as streptozotocin-induced diabetes, pancreatic proteases may have some effects on the disaccharidase activities through modulating the enzyme conformation or their degradation rate.…”

Section: Discussionmentioning

confidence: 99%

Changes of the activity and content of sucrase-isomaltase complex in the intestinal mucosa during the development of streptozotocin-induced diabetes in rats.

Goda

Hosoya

Moriuchi

1983

Journal of Nutritional Science and Vitaminology, J Nutr Sci Vit

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“…In light of the gradient of sucrase-isomaltase activities, such a pattern of gene expression suggests that the majority of the enzyme complex is synthesized when the cells are in the lower part of the villus and that there is probably a slow turnover of the enzyme complex. Furthermore, since the enzyme is synthesized as prosucrase-isomaltase, which is then cleaved into sucrase-isomaltase by pancreatic proteases at the brush border membrane (Semenza, 1979), it is plausible that the proenzyme is gradually cleaved as the cells migrate from the lower part of the villus to the villus tips, although Montgomery et al (1981) observed full activity of the uncleaved enzyme complex.…”

Section: Genes With Decreasing Gradient Of Expression From Villus Basmentioning

confidence: 99%

Patterns of gene expression along the crypt-villus axis in mouse jejunal epithelium

Cheng

Bjerknes

1996

Anat. Rec.

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Background There is considerable interest in gene expression along the crypt‐villus axis of the small intestinal epithelium, particularly in the identification of genes expressed in intestinal crypts. Methods In an attempt to identify crypt‐expressed genes, single‐stranded cDNA made from normal mouse jejunal epithelium was used in subtractive hybridization against single‐stranded cDNA from epithelium from which crypt cells were depleted by 2,000 rads of gamma irradiation. Partial DNA sequence and in situ hybridization of 72 resulting clones were determined. Results The sequence of 45 clones matched previously published genes. Gene expression patterns fell into three categories: expression throughout the crypt‐villus axis, expression restricted to the villus, and expression restricted to the crypt. Clones in the first two categories could be further divided into three subgroups: those with uniform expression, those with an increasing gradient of expression, and those with a decreasing gradient of expression along the crypt‐villus axis. Twenty two clones showed a stronger expression in crypt and lower villus cells, four of these were differentially localized to the crypt. Two of the crypt localized clones were uniformly expressed throughout the crypt, expression of one was stronger in the lower crypt, and expression of the remaining clone was enhanced Paneth cells. We report the full‐length cDNA sequence of the Paneth‐cell‐enhanced clone. Conclusions The screen isolated crypt‐expressed genes that may prove useful tools in the study of crypt biology. In a companion report, we characterize one of the crypt clones. © 1996 Wiley‐Liss, Inc.

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Rat intestinal microvillus membrane sucrase-isomaltase is a single high molecular weight protein and fully active enzyme in the absence of luminal factors

Cited by 35 publications

References 13 publications

Evidence of degradation process of sucrase-isomaltase in jejunum of adult rats

Evidence of degradation process of sucrase-isomaltase in jejunum of adult rats

Changes of the activity and content of sucrase-isomaltase complex in the intestinal mucosa during the development of streptozotocin-induced diabetes in rats.

Patterns of gene expression along the crypt-villus axis in mouse jejunal epithelium

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