Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.2.1.26 (invertase)
4,927 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Adenocarcinoma of the colon is one of the most prevalent and lethal of all human malignancies. The early diagnosis and management of this disease could be improved if biological markers, whose expression was restricted to malignant colon cells, were identified. Sucrase-isomaltase is a glycoprotein hydrolase expressed throughout the small intestine and fetal colon but not in the normal adult colon. This study shows that the expression of enzymatically active sucrase-isomaltase is a ubiquitous property of primary and metastatic colon adenocarcinoma. Significant sucrase enzyme activity (i.e., greater than 5 mU/mg protein) was observed in 16 colon carcinomas but not in adjacent normal colon mucosa. Sucrase-isomaltase messenger RNA was identified in all tumors using reverse transcriptase polymerase chain reaction. Using a quantitative polymerase chain reaction analysis, this study shows that the amount of sucrase-isomaltase messenger RNA in tumors examined (3.4 x 10(-8) to 3.19 x 10(-7) micrograms/micrograms total RNA) was greater than in adjacent mucosa (0 to 3.4 x 10(-8) micrograms/micrograms total RNA). This induction of sucrase-isomaltase messenger RNA and enzyme activity was corroborated by immunostaining. Of 30 colon adenocarcinomas examined, 80% were positive for sucrase-isomaltase. In addition, all colon carcinoma metastases examined were positive for sucrase-isomaltase. The staining pattern was distinct and demarcated tumor cells from the surrounding histologically normal tissue. No sucrase-isomaltase staining was seen in normal mucosa from the same patients. With the exception of lung, no sucrase-isomaltase immunostaining was observed in a variety of examined noncolonic adenocarcinomas. Thus, the specificity and ubiquity of sucrase-isomaltase expression in adenocarcinomas of the colon can be exploited to improve the clinical management of this disease. In addition, studies on the structure of the sucrase-isomaltase gene and its regulatory elements should contribute toward understanding the alteration of gene expression by oncogenic transformation of the colonic mucosa.
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PMID:Expression of enzymatically active sucrase-isomaltase is a ubiquitous property of colon adenocarcinomas. 170 85

The effects of epidermal growth factor (EGF) on disaccharidase activity in intestinal epithelial cells were studied in mice. In salivectomised mice, the sucrase and maltase activities decreased significantly compared to the control group. When EGF was given to salivectomised mice, the sucrase and maltase activities rose, but still remained below the normal values. These results show that the submaxillary glands produced another factor, beside EGF, which induced glycoprotein enzyme formation in the Golgi complex.
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PMID:Effect of epidermal growth factor on disaccharidase activity in intestinal epithelial cells of mice. 191 36

Carboxypeptidase Y, a yeast vacuolar glycoprotein was expressed in oocytes from Xenopus laevis and its biosynthesis and sorting were examined. In yeast, targeting to the vacuole, the functional equivalent of the lysosome, is not mannose-6-phosphate-receptor dependent. It was found that carboxypeptidase enters the secretory pathway of the oocyte and is there glycosylated, phosphorylated in the carbohydrate part and delivered to the lysosome. Deletion of an amino acid sequence, previously shown to determine intracellular targeting of this enzyme in yeast, caused a loss of phosphorylation and mislocalization of carboxypeptidase Y into the oocyte medium. Inhibition of glycosylation of carboxypeptidase by tunicamycin did not lead to its secretion. In-frame fusion of the targeting domain to a secretory yeast glycoprotein, invertase, did not prevent its secretion. However, a hybrid containing 80% carboxypeptidase abolished invertase secretion. The results indicate that the vacuolar protein-targeting signal from yeast carboxypeptidase can, in principal, function in a higher eukaryote.
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PMID:The vacuolar protein-targeting signal of yeast carboxypeptidase is functional in oocytes from Xenopus laevis. 199 65

BioBreed (BB) Wistar rats develop diabetes mellitus, which closely resembles the human disease, in 50% of progeny. Intestinal sucrase-alpha-dextrinase, a glycoprotein hydrolase of the enterocyte's brush border consisting of 140-kDa alpha-dextrinase and 125-kDa sucrase subunits, is essential for surface digestion of carbohydrate nutrients. Although its catalytic characteristics were found to be maintained in the diabetic state, the structure of the subunits, as compared with normal Wistar rats, was altered in the BB rat within 2 days of the onset of diabetes. Its capacity to react in a solid-phase immunoassay was reduced by 50%; when examined by 6% acrylamide electrophoresis, the sucrase subunit was increased in mass by 5 kDa and, in some BB rats, the dextrinase subunit was reduced by 5 kDa. Intact rats labeled intraintestinally with [35S]methionine displayed the alteration within 6 h of synthesis, indicating that nonenzymatic glycosylation could not account for the structural change. This mass change was not seen in streptozotocin-induced diabetes and was independent of the plasma glucose concentration or the degree of acidosis. Deglycosylation with peptide N-glycosidase indicated that the N-linked chains of the normal dextrinase subunit (11 kDa) have twice the mass of those in the BB rat (6 kDa) and that the sucrase subunit may have an increased mass of O-linked chains. Overall, these experiments point to changes in glycosylation as a mechanism of structural alteration in congenital diabetes. Despite persistence of the insulin-dependent diabetes, the subunit pattern eventually became indistinguishable from normal, but at differential rates (21 days and 35 days, respectively, for sucrase and dextrinase subunits).
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PMID:Sucrase-alpha-dextrinase in diabetic BioBreed rats: reversible alteration of subunit structure. 199 46

Invertase (EC 3.2.1.26) was purified to homogeneity from exponentially growing cells of Schizosaccharomyces pombe fully de-repressed for synthesis of the enzyme, and was shown to be a high-molecular-mass glycoprotein that can be dissociated in the presence of 8 M-urea/1% SDS into identical subunits with an apparent molecular mass of 205 kDa. The carbohydrate moiety, accounting for 67% of the total mass, is composed of equimolar amounts of mannose and galactose. There is a small amount of glucosamine, which is probably involved in the linkage to the protein moiety, since the enzyme is sensitive to treatment with endoglycosidase H. The composition of the carbohydrate moiety resembles that found in higher-eukaryotic glycoproteins and differs from glycoproteins found in Saccharomyces cerevisiae. The protein portion of each subunit is a polypeptide of molecular mass 60 kDa, very similar to the invertase of Sacch. cerevisiae. Both proteins cross-react with antibodies raised against the protein fractions of the other, indicating that the two enzymes are similar.
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PMID:Purification and characterization of the invertase from Schizosaccharomyces pombe. A comparative analysis with the invertase from Saccharomyces cerevisiae. 218 35

A blotting method is described to detect enzymes that do not normally yield a colored product. The method can be used for dot blotting as well as blotting after gel electrophoresis of many enzymes if the reactions they catalyze can be coupled to an oxidase or a dehydrogenase. The latter, designated "auxiliary enzymes," are preimmobilized on membranes of nitrocellulose or positively charged nylon and the reaction they catalyze is coupled with reduction of tetrazolium salt to yield colored formazan on areas of the transfer membrane occupied by the blotted enzymes. In the examples reported here, preimmobilized glucose oxidase, L-amino acid oxidase, xanthine oxidase, malate dehydrogenase, and a mixture of hexokinase and glucose-6-phosphate dehydrogenase were used as auxiliary enzymes to detect blotted invertase, leucine aminopeptidase, purine nucleoside phosphorylase, fumarase, and adenylate kinase, respectively. Detection limits varied, but never exceeded 100 ng for these enzymes. After blotting from polyacrylamide gels, the fumarase assay was the most sensitive of those investigated, detecting 10 ng of enzyme used for electrophoresis. Invertase, a glycoprotein, was detected with higher sensitivity on nitrocellulose membranes when concanavalin A was present on the membrane in addition to the auxiliary enzyme, glucose oxidase. On blots from isoelectric focusing gels, the assay detected two isozymes of purine nucleoside phosphorylase in a sample from calf spleen and at least five isozymes of this enzyme in lysates from human red cells.
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PMID:Activity staining of blotted enzymes by reaction coupling with transfer membrane-immobilized auxiliary enzymes. 245 38

Glycoproteins immobilized on membranes can be detected with high selectivity and sensitivity by the four-step procedure described in this work. The glycoproteins are first oxidized by sodium periodate and then polyacrylic polyhydrazides are coupled to the aldehyde groups generated in the sugar part of the glycoproteins. In the third step, a glycoenzyme, such as horseradish peroxidase, is coupled to the remaining hydrazide groups on the polymer through the aldehydes formed in its glycan chains. In the last step, the visualization of glycoproteins is achieved through the reaction product of the bound glycoenzyme. The sensitivity of the glycoprotein detection is most critically dependent on the hydrazide reagent. Thus, dihydrazides were not satisfactory, a trihydrazide was better, and polyhydrazides were the best. Two different polyhydrazides were used. One was based on acrylamide and the other on N-acryloyl-tris(hydroxymethyl)aminomethane. The second one proved to be superior because it gave higher sensitivity with no detectable background staining. We have also investigated the influence of various reaction conditions on staining of glycoproteins having oligomannose and N-acetyllactosamine type glycan chains. Some of them, invertase and fetuin, could be detected with sensitivity similar to that of silver staining in gels and colloidal gold staining on the membranes. The detection of small quantities of Endo H-deglycosylated glycoproteins was possible under standard conditions only if several N-acetylglucosamine residues remained bound to the protein.
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PMID:Polyacrylic polyhydrazides as reagents for detection of glycoproteins. 247 93

The inactivation of external yeast invertase by irradiation in dilute aqueous solution has been investigated. The contributions of the individual radical species from water radiolysis to inactivation and amino acid degradation were estimated from the results of experiments in which solutions were saturated with nitrogen, nitrous oxide or oxygen, and on addition of hydroxyl radical scavengers. Under conditions where inactivation by hydroxyl radicals predominates, the rate of inactivation increased with increasing dose, indicating that in the initial stages of the radiolysis the mannose-rich oligosaccharide chains of the glycoprotein protect the polypeptide chain from radical attack. Amino acid analysis of the irradiated external invertase showed that there was significant destruction of tyrosine, phenylalanine, methionine and histidine residues. Destruction of methionine and histidine residues may be responsible for the free radical-induced inactivation of this enzyme.
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PMID:The radiation-induced inactivation of external yeast invertase in dilute aqueous solution. 256 93

We have evaluated the participation of mannose receptors on the surface of stimulated macrophages in the phagocytosis of Candida albicans in vitro. A dose-dependent 8.6 to 88.3% reduction of phagocytosis was observed in the presence of 0.5 to 5.0 mg/ml of the mannose-rich glycoprotein invertase (either native or denatured) in the incubation medium. Macrophages plated onto substrates coated with poly-L-lysine-mannan also showed a 99% reduction of phagocytic activity toward Candida albicans, but phagocytosis of IgG-coated erythrocytes was not inhibited under the same conditions. These results indicate that mannose receptors are involved in one of the initial steps of phagocytosis of Candida albicans by macrophages.
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PMID:Participation of mannose receptors on the surface of stimulated macrophages in the phagocytosis of glutaraldehyde-fixed Candida albicans, in vitro. 270 Apr 33

Each of the three high-mannose type glycoproteins studied, acid phosphatase, invertase, and glucose oxidase, could be specifically cross-linked through its carbohydrate chains. The procedure involves periodate oxidation of carbohydrate residues followed by reaction of the generated aldehyde groups with adipic acid dihydrazide as a cross-linker. The amount and size as well as solubility of the formed polymers could be efficiently controlled by varying the reaction conditions, i.e., the oxidation degree and the concentrations of glycoproteins, cross-linker, and hydrogen ions during the cross-linking reaction. It was found that the quantity and size of polymers increased with oxidation degree and protein concentration and by lowering the pH. When the protein concentration was above and pH below certain values, depending on the glycoenzyme, insoluble polymers formed. The soluble cross-linked polymers retained a high level of original activity, and the minor decrease in specific activity noticed was shown to occur during the periodate oxidation step. The cross-linked glycoenzymes are much more resistant to denaturation by high temperature and by changes in pH, demonstrating the usefulness of this method in preparation of the stabilized glycoprotein derivatives.
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PMID:Preparation of the stabilized glycoenzymes by cross-linking their carbohydrate chains. 284 Aug 55


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