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)

Among the collection of temperature-sensitive secretion mutants of Saccharomyces cerevisiae, sec11 mutant cells are uniquely defective in signal peptide processing of at least two different secretory proteins. At 37 degrees C, the restrictive growth temperature, sec11 cells accumulate core-glycosylated forms of invertase and acid phosphatase, each retaining an intact signal peptide. In contrast, other sec mutant strains in which transport of core-glycosylated molecules from the endoplasmic reticulum is blocked show no defect in signal peptide cleavage. A DNA fragment that complements the sec11-7 mutation has been cloned. Genetic analysis indicates that the complementing clone contains the authentic SEC11 gene, and that a null mutation at the SEC11 locus is lethal. The DNA sequence of SEC11 predicts a basic protein (estimated pI of 9.5) of 167 amino acids including an NH2-terminal hydrophobic region that may function as a signal and/or membrane anchor domain. One potential N-glycosylation site is found in the 18.8-kD (Sec 11p) predicted protein. The mass of the SEC11 protein is very close to that found for two of the subunits of the canine and hen oviduct signal peptidases. Furthermore, the chromatographic behavior of the hen oviduct enzyme indicates an overall basic charge comparable to the predicted pI of the Sec11p.
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PMID:SEC11 is required for signal peptide processing and yeast cell growth. 328 43

The antibiotic tetaine inhibits in Candida albicans the biosynthesis of two important cell wall constituents, chitin and mannoprotein. This effect is a consequence of inactivation of the enzyme glucosamine-6-phosphate synthetase. Due to the lack of glucosamine-6-phosphate the effective secretion of mannoprotein enzymes, acid phosphatase and invertase, by Candida albicans spheroplasts is inhibited. In the presence of tetaine, probably a modified mannoprotein, lacking a branched polymannan, is synthesized. The antibiotic action decreases the viability of Candida albicans cells, especially that of mycelial forms of this fungus.
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PMID:Antibiotic tetaine--a selective inhibitor of chitin and mannoprotein biosynthesis in Candida albicans. 353 88

The SNF2 and SNF5 genes are required for derepression of SUC2 and other glucose-repressible genes of Saccharomyces cerevisiae in response to glucose deprivation. Previous genetic evidence suggested that SNF2 and SNF5 have functionally related roles. We cloned both genes by complementation and showed that the cloned DNA was tightly linked to the corresponding chromosomal locus. Both genes in multiple copy complemented only the cognate snf mutation. The SNF2 gene encodes a 5.7-kilobase RNA, and the SNF5 gene encodes a 3-kilobase RNA. Both RNAs contained poly(A) and were present in low abundance. Neither was regulated by glucose repression, and the level of SNF2 RNA was not dependent on SNF5 function or vice versa. Disruption of either gene at its chromosomal locus still allowed low-level derepression of secreted invertase activity, suggesting that these genes are required for high-level expression but are not directly involved in regulation. Further evidence was the finding that snf2 and snf5 mutants failed to derepress acid phosphatase, which is not regulated by glucose repression. The SNF2 and SNF5 functions were required for derepression of SUC2 mRNA.
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PMID:Molecular analysis of SNF2 and SNF5, genes required for expression of glucose-repressible genes in Saccharomyces cerevisiae. 354 May 98

Biopsy specimens from 29 adenomas, 17 adenocarcinomas, and 6 synchronous adenomas in cancer patients and from uninvolved mucosa of all main segments of the large bowel were examined histologically and assayed for a series of organelle marker enzymes. Six enzymes--lactase, sucrase, alkaline phosphatase, 5'-nucleotidase, acid phosphatase, and N-acetyl-beta-D-glucosaminidase--showed less activity in adenomas than in adjacent uninvolved mucosa and in specimens from controls. Cancer tissue had higher gamma-glutamyltransferase and lower lactase, alkaline and acid phosphatases, and N-acetyl-beta-D-glucosaminidase activities than specimens from uninvolved mucosa in cancer patients and control patients. Enhanced alkaline phosphatase and N-acetyl-beta-D-glucosaminidase activities were seen in uninvolved mucosa of cancer patients as compared with those of adenoma and control patients. Evidence has been found for multienzyme analysis to identify adenomas with signs of malignant transformation and carcinomas with poor prognosis.
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PMID:Enzyme activities in biopsy specimens from large-bowel mucosa in colorectal adenomas and carcinomas. 362 77

The role of structural signals in intercompartmental transport has been addressed by the isolation of yeast invertase (SUC2) mutations that cause intracellular accumulation of active enzyme. Two mutations that delay transport of core-glycosylated invertase, but not acid phosphatase, have been mapped in the 5' coding region of SUC2. Both mutations reduce specifically the transport of invertase to a compartment, presumably in the Golgi body, where outer chain carbohydrate is added. Subsequent transport to the cell surface is not similarly delayed. One mutation (SUC2-s1) converts an ala codon to val at position -1 in the signal peptide; the other (SUC2-s2) changes a thr to an ile at position +64 in the mature protein. Mutation s1 results in about a 50-fold reduced rate of invertase transport to the Golgi body which is attributable to defective signal peptide cleavage. While peptide cleavage normally occurs at an ala-ser bond, the s1 mutant form is processed slowly at the adjacent ser-met position giving rise to mature invertase with an N-terminal met residue. s2 mutant invertase is transported about sevenfold more slowly than normal, with no delay in signal peptide cleavage, and no detectable abnormal physical property of the enzyme. This substitution may interfere with the interaction of invertase and a receptor that facilitates transport to the Golgi body.
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PMID:Invertase signal and mature sequence substitutions that delay intercompartmental transport of active enzyme. 388 71

The intracellular localization of invertase endocytosed by rat liver was investigated by analytical centrifugation in sucrose and Percoll gradients of mitochondrial fractions originating from rats killed 15 h after injection. After isopycnic centrifugation in a sucrose gradient, invertase is located in higher density zones than acid hydrolases. The difference between the distribution of invertase and that of acid hydrolases increases with the amount of invertase injected. When the invertase dose is sufficiently high, a change of lysosomal enzyme distribution is clearly visible. It consists in the shift of a proportion of these enzymes to higher density regions where invertase is located. The proportion of hydrolase activity affected by invertase is different for each enzyme measured; it is the least pronounced for acid phosphatase, and most for acid deoxyribonuclease and arylsulfatase. A pretreatment of the rat with Triton WR 1339 considerably decreases the equilibrium density of structures bearing invertase. Nevertheless invertase distribution is quite distinct from that of the bulk of lysosomal enzymes that are recovered in lower density zones of the gradient; on the other hand the invertase injection to rats treated with Triton WR 1339 causes a spreading of the acid hydrolase distribution towards higher density zones. The distribution of acid hydrolases and invertase in a Percoll gradient depends on the sucrose concentration of the solvent. It is shifted towards higher densities when the sucrose concentration increases. The phenomenon is more important for invertase. These results are best explained by supposing that invertase accumulates in a distinct population of lysosomes that can be individualized as a result of the density increase they are subjected to by the invertase they accumulate. It is proposed that these lysosomes mainly originate from non-parenchymal cells of the liver.
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PMID:Effect on lysosomes of invertase endocytosed by rat-liver. 402 43

In Neurospora, invertase is predominately an extracellular enzyme, and acid phosphatase is partially external in location. Both extracellular invertase and acid phosphatase were rapidly and quantitatively inactivated by acid treatment (pH 1.3). When such acid-treated cells were incubated with a suitable carbon source, a substantial regeneration of invertase activity occurred, but no restoration of acid phosphatase could be detected. The regeneration of invertase does not occur by renaturation of the inactivated enzyme, nor by secretion of a preexisting intracellular pool of invertase, but instead requires de novo enzyme synthesis. Invertase synthesis was partially repressed by glucose and mannose and was completely inhibited by 2-deoxyglucose. Acetate was found to inhibit invertase regeneration and the transport and incorporation of uracil and leucine. Several potential inhibitors of transcription, including alpha-amanitin, 5-fluorouracil, actinomycin D, and three derivatives of rifamycin, were ineffective in preventing invertase regeneration and in inhibiting the synthesis of ribonucleic acid. Conidia appeared to be very poorly permeable to these compounds.
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PMID:Regeneration of invertase in Neurospora crassa. 426 89

1. Homogenates of the mucosa of the small intestine of the guinea pig were separated by fractional sedimentation into seven different fractions. The enzymic properties of some of these subcellular fractions were compared with those obtained from the mucosa of the small intestine of the rabbit and cat. 2. The enzymic properties of the low-speed sediment (15000g-min.) were investigated and it was shown that invertase and alkaline ribonuclease were predominantly located in this subcellular fraction, whereas alkaline phosphatase, aryl-amidase, acid phosphatase, acid ribonuclease and phosphoprotein phosphatase, though true constituents of this fraction, occurred to varying degrees in other subcellular structures also. 3. It was shown that the most probable source of the enzymic activities observed in the low-speed sediment was the brush border. Electron micrographs of the purified brush-border fraction indicated vesicles derived from the brush-border membrane. 4. A method is described for the fractionation of mucosal homogenates into a brush border-plus-nuclei fraction, a mitochondrial fraction, a microsomal fraction and a particle-free supernatant. The fractions were shown to be relatively pure, as indicated by the distribution of invertase, DNA, succinate dehydrogenase, glucose 6-phosphatase and 6-phosphogluconate dehydrogenase. 5. Most of the activity of four lysosomal enzymes present in the nuclei-free homogenate was sedimented at 375000g-min., suggesting the occurrence of lysosomal particles in mucosal homogenates. 6. Further fractionation of the microsomal membranes into three fractions is described. The enzymic composition of the membrane fractions is given and discussed in relation to their structure as seen in electron micrographs.
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PMID:Studies on the fractionation of mucosal homogenates from the small intestine. 428 74

Some intestinal enZymes were assayed which were related to: (i) Cellular proliferation, for example, aspartate carbamoyltransferase, thymidine kinase, uridine kinase, and dihydroorotase; (ii) cellular differentiation, for example, lactase, invertase, maltase, alkaline phosphatase, and dipeptidase; and (iii) lysosomes, for example, beta-glucuronidase, acid beta-galactosidase, and acid phosphatase. These enzymatic determinations can be used to distinguish the crypt from the villus during healthy or diseased states.
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PMID:Intestinal enzymes: indicators of proliferation and differentiation in the jejunum. 431 2

After 16 hr of incubation in a low-phosphate, aerated medium, bakers' yeast was obtained with a high titer of acid phosphatase (EC 3.1.3.2) and beta-fructofuranosidase (EC 3.2.1.26). All of the beta-fructofuranosidase and 75% of the acid phosphatase were easily released by mechanical disruption in a French pressure cell. The cell wall suffered a limited number of cracks, but this was sufficient for the co-release of these enzymes. Both enzymes were subject to autolytic release, although correlation was inconclusive because of the relative instability of acid phosphatase. The data are consistent with the bulk of the two enzymes being located in the periplasmic space. Ethylacetate treatments yielded ghosts with high beta-fructofuranosidase but low acid phosphatase activities. The surviving acid phosphatase was not representative of that in live cells. It was resistant to release by mechanical disruption and showed a high susceptibility to heat inactivation. The beta-fructofuranosidase in live cells and in ethylacetatetreated cells exhibited polydispersity in heat inactivation susceptibility; but the kinetics were indistinguishable, and facile release by mechanical disruption was shown in both cases.
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PMID:Location of acid phosphatase and -fructofuranosidase within yeast cell envelopes. 456 42


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