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Query: UNIPROT:P06889 (Mol)
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The intergenic regions between the duplicated amylase coding regions (Amy) of D. melanogaster and D. teissieri were sequenced. Their lengths in D. melanogaster and D. teissieri were 4,536 bp and 4,621 bp, respectively. Since homology between the upstream regions of the two duplicated genes was found up to 450 bp from the initiation codon of the Amy genes, the ancestral Amy coding region duplicated together with at least 450 bp of the 5'-flanking region as one unit. Comparison of the regions between the two species revealed that the level of divergence was very heterogeneous. Although the mean level of the nucleotide difference in this region was 0.107, no nucleotide substitution was found in four subregions whose sizes were more than 100 bp. Since the probability of these four subregions being completely conserved between D. melanogaster and D. teissieri was very low, these subregions were considered to have relatively important roles in evolution. Large insertions and deletions were not observed in this region but small ones were observed all over the region except for an about 1-kb subregion. This 1-kb region corresponded to an open reading frame encoding a protein which had some sequence identity with the proteins of the serine protease inhibitor superfamily (serpin). Since we could find a transcript of this gene and the synonymous substitution rate was higher than the replacement substitution rate, we suggest that this gene encodes an active serpin in Drosophila.
J Mol Evol 1997 Jul
PMID:Molecular analysis of the intergenic region of the duplicated Amy genes of Drosophila melanogaster and Drosophila teissieri. 921 32

Previous studies have suggested that salivary amylase and proline-rich protein are sorted differently when expressed in AtT-20 cells (Castle, A.M., L.E. Stahl, and J.D. Castle. 1992. J. Biol. Chem. 267:13093- 13100; Colomer, V., K. Lal, T.C. Hoops, and M.J. Rindler. 1994.EMBO (Eur. Mol. Biol. Organ.) J. 13:3711- 3719). We now show that both exocrine proteins behave similarly and enter the regulated secretory pathway as judged by immunolocalization and secretagogue- dependent stimulation of secretion. Analysis of stimulated secretion of newly synthesized proline-rich protein, amylase, and endogenous hormones indicates that the exogenous proteins enter the granule pool with about the same efficiency as the endogenous hormones. However, in contrast to the endogenous hormones, proline-rich protein and amylase are progressively removed from the granule pool during the process of granule maturation such that only small portions remain in mature granules where they colocalize with the stored hormones. The exogenous proteins that are not stored are recovered from the incubation medium and are presumed to have undergone constitutive-like secretion. These results point to a level of sorting for regulated secretion after entry of proteins into forming granules and indicate that retention is essential for efficient storage. Consequently, the critical role of putative sorting receptors for regulated secretion may be in retention rather than in granule entry.
 ...
PMID:Passive sorting in maturing granules of AtT-20 cells: the entry and exit of salivary amylase and proline-rich protein. 921 80

The digestive enzyme alpha-amylase in Pecten maximus has been purified from the digestive gland, where it is present as two isoforms, In order to gain information on its structure and regulation, a digestive gland cDNA library, constructed in lambda phage Zap II (Stratagene, La Jolla, Calif., U.S.A.), was screened with a shrimp alpha-amylase cDNA probe. Only 0.02% of the clones were positive, and the longest clone, having a size of 1700 bp and identical to that of the mRNA, was fully sequenced. It contains the complete cDNA coding frame for one of the amylase isoforms of P. maximus. The deduced protein sequence is 508 amino acids long, with a putative 18 amino acid, highly hydrophobic signal peptide and a mature enzyme of 489 residues. The molecular weight corresponds to 54,500 Da and the calculated isoelectric point is 6.76. Locations of conserved sequences confirms the high level of similarity with the other members of the family.
Mol Mar Biol Biotechnol 1997 Sep
PMID:Amylase on Pecten maximus (Mollusca, bivalves): protein and cDNA characterization; quantification of the expression in the digestive gland. 928 61

Reproduction of pancreatic iron overload in an animal model has been difficult to achieve primarily because of the first-pass extraction of iron by the liver. We hypothesized that portacaval shunting would avoid this hepatic phenomenon and increase pancreatic iron deposition. An end-to-side portacaval shunt was surgically created in male Sprague-Dawley rats, and they were subsequently fed a carbonyl iron-supplemented diet for 17 weeks. This resulted in marked iron accumulation in the pancreas (1621 +/- 188 micrograms/g) compared to minimal deposition in sham-operated rats fed the same diet (138 +/- 53 micrograms/g). Iron deposition in the acinar and centroacinar cells was confirmed histologically by Gomori staining, as well as by ultrastructural examination. Iron overloading was associated with enhanced oxidative stress evidenced by a twofold increase in the levels of glutathione disulfide and thiobarbituric acid-reactive substances. Also, adducts of proteins with malondialdehyde and 4-hydroxynonenal were demonstrated in acinar and ductal cells. Other apparent consequences of iron overload were a 50% reduction in pancreatic amylase content and a decrease in pancreatic protein concentration. These hypotrophic changes were associated with a reduced mass of zymogen granules in the acinar cells noted histologically. Our results show that a combination of portacaval shunting and carbonyl iron feeding achieve pancreatic iron overload and support the role of oxidative stress in the pathogenesis of iron-induced damage in the pancreas.
Exp Mol Pathol 1997 Apr
PMID:Iron overload in the rat pancreas following portacaval shunting and dietary iron supplementation. 931 87

The role of pancreas specific transcription factor (PTF1) in thyroxine (T4) modulation of amylase gene expression in suckling rats was evaluated. Electrophoretic mobility shift assay (EMSA) was used to determine the PTF1 binding activity by the amount of a synthetic oligonucleotide containing the amylase enhancer sequence bound by nuclear protein extracts. Nuclear protein from rat pancreata showed a developmental increase of PTFI activity correlated with age. To study the action of T4, pups were made hyperthyroid by T4 injection and hypothyroid by feeding propylthiouracil (PTU) to the lactating dams. EMSA of nuclear proteins isolated from these groups showed an increase in PTF1 binding activity in the T4 group and a decrease in the PTU group. Concomitantly, T4 increased, while PTU decreased both amylase enzyme and mRNA concentrations. T4 replacement reversed the effect of PTU on PTF1 binding, amylase enzyme activity and mRNA levels. To examine the age dependence of T4 effects, T4 was injected to pups for 5 days prior to killing at the age of 15, and 25 days. T4 was effective when given at an earlier age (15 days) but not at a later stage (25 days) in increasing amylase activity and amylase mRNA levels. Nuclear proteins isolated from pancreata of these groups showed an increase in PTF1 binding activity in the T4-treated 15-day-olds but not in the 25-day-olds in comparison to their corresponding age matched littermates. These results suggest that PTF1 is an important intermediary in T4 modulation of amylase gene expression during ontogeny of the rat exocrine pancreas.
Mol Cell Endocrinol 1994 May
PMID:Thyroxine control of pancreatic amylase gene expression: modulation of PTF1 binding activity. 939 63

Genomic DNA fragments encoding a salivary gland-specific alpha-amylase gene, Amylase I (Amy I), and an additional amylase, Amylase II (AmyII) of the yellow fever mosquito, Aedes aegypti, were isolated and characterized. Two independently isolated DNA fragments, G34-F and G34-14A, encode polymorphic alleles of Amy I. A 3.2 kilobase (kb) EcoR I fragment of G34-F, F2, has been sequenced in its entirety and contains 832 base pairs (bp) of the 5'-end, non-coding and putative promoter regions that are adjacent to 2.4 kb of the Amy I coding region. One intron, 59 bp in length, is found towards the 3'-end of the clone. A third genomic clone, 3A, corresponding to Amy II, was sequenced and shown not to contain the primary DNA sequence that encodes the 260 amino acid region that uniquely characterizes the amino terminal end of the Amy I product. Amy I was assigned by restriction fragment length polymorphism (RFLP) mapping to chromosome 2 (23.0 cM) and Amy II to chromosome 1 (44.0 cM). Amy I and Amy II are highly polymorphic and there may be multiple linked copies at each locus. Comparisons between Amy I and Amy II are presented for the putative promoter and conceptual translation products. The identification of two distinct amylase genes and their separate linkage assignments provides evidence for a multigene family of alpha-amylases in Ae. aegypti.
Insect Biochem Mol Biol
PMID:Evidence for two distinct members of the amylase gene family in the yellow fever mosquito, Aedes aegypti. 944 77

Silymarin can be extracted from the milk thistle, and silibinin is the main component of the plant extract. Possibly due to their antioxidant and membrane-stabilizing properties, the compounds have been shown to protect different organs and cells against a number of insults. Thus liver, kidney, erythrocytes and platelets have been protected from the toxic effects of ethanol, carbon tetrachloride, cold ischemia and drugs, respectively. The effect of silibinin on endocrine and exocrine pancreas, however, has not been studied. We therefore investigated whether silibinin treatment attenuates cyclosporin A (CiA) toxicity on rat endocrine and exocrine pancreas. Groups of 15 male Wistar rats were treated for 8 days with CiA and/or silibinin. On day 9, endocrine and exocrine pancreatic functions were tested in vitro. At the end of the treatment period, blood glucose levels in vivo were significantly higher in rats treated with CiA while silibinin did not affect glucose levels. In vitro, insulin secretion was inhibited after treatment with silibinin, but amylase secretion was not affected. After treatment with CiA both insulin and amylase secretion were reduced. Silibinin and CiA had an additive inhibitory effect on insulin secretion, but silibinin attenuated CiA-induced inhibition of amylase secretion. Despite CiA treatment, amylase secretion was in fact restored to normal with the highest dose of silibinin. Thus silibinin inhibits glucose-stimulated insulin release in vitro, while not affecting blood glucose concentration in vivo. This combination of effects could be useful in the treatment of non-insulin-dependent diabetes mellitus. Furthermore, silibinin protects the exocrine pancreas from CiA toxicity. As this inhibitory effect is probably unspecific, silibinin may also protect the exocrine pancreas against other insult principles, such as alcohol.
Cell Mol Life Sci 1997 Dec
PMID:Silibinin, a plant extract with antioxidant and membrane stabilizing properties, protects exocrine pancreas from cyclosporin A toxicity. 944 43

This study was performed to evaluate the effects of different doses of hydrocortisone (1, 10 and 25 mg/kg/day) administered for 1, 3 and 8 days on pancreatic enzyme storage in rats. The enzyme content in both pancreas homogenates and in individual isolated zymogen granules (ZGs) was measured using standard biochemical assays and flow cytometry, respectively. Hydrocortisone did not alter the total amount of pancreatic DNA but increased the pancreas enzyme content in a time-dose-dependent way. Amylase activity was significantly increased after hydrocortisone administration at day +8 when 10 mg/kg/day was used, and from the first day of treatment when 25 mg/kg/day was administered. A significant increase in trypsin activity was also observed in response to 25 mg/kg/day of hydrocortisone but only from the third day of treatment onwards. As compared with control rats, chronic administration of either 1 or 10 mg/kg/day of hydrocortisone did not alter significantly either the size or the percentage of the two ZG subpopulations (Z1 and Z2) identified in the pancreas by flow cytometry; in addition, no significant changes were observed in the mean amylase content per individual granule, although its mean concentration increased in rats treated with 10 mg/kg/day for 3 and 8 days. Nevertheless, when 25 mg/kg/day of hydrocortisone were administered for 1 and 3 days, a significant increase in the proportion of Z1 ZGs was observed, which may be related to the formation of new and smaller ZGs. When a very high dose of hydrocortisone (25 mg/kg/day) was used, an overall increase in the pancreatic enzyme content related to an increase in the mean amylase content per individual ZG was observed; this effect was apparent from the first day of treatment in the Z1 subset of ZGs and from day +3 in the Z2 subpopulation. Only a high concentration of hydrocortisone was able to alter the enzyme storage process in individual zymogen granules, but they maintain a normal enzyme load at lower hydrocortisone doses.
J Steroid Biochem Mol Biol 1997 Aug
PMID:Hydrocortisone induces an increase of amylase content in individual zymogen granules from rat pancreas. 944 47

Expression of alpha-amylase genes during seedling development plays a key role in production of sugar from the starch stored in the cereal seed. Rice alpha-amylase Amy3D promoter/GUS constructs in transgenic rice cell lines were studied to identify cis elements in the promoter of this metabolite-regulated gene. Three sequences having the greatest effects on Amy3D gene expression included the amylase element (TATCCAT), the CGACG element, and a G box-related element (CTACGTGGCCA). These promoter cis elements are needed for high-level expression of Amy3D under conditions of sugar starvation. The involvement of G box cis-elements in environmental stress responses suggest a link between the nutrient stress and the environmental stress responses of the plant.
Plant Mol Biol 1998 Feb
PMID:Three cis-elements required for rice alpha-amylase Amy3D expression during sugar starvation. 948 74

alpha-Amylases from Drosophila virilis and D. repleta were partially purified by ion exchange chromatography. The two amylases share common characteristics for pH and cations effects, although with slight differences. D. virilis has optimal activity at pH 6.6 and D. repleta at pH 7.2. Calcium, sodium, and potassium cations activate amylolytic activity in both species but Ba2+ has an activation effect in D. repleta only. In contrast, there are major differences in thermal offbility and kinetics among amylases of the two species. D. virilis amylase is much more stable at high temperature and the optimal temperatures are very different between the two species, respectively, 45 degrees C and 30 degrees C for D. virilis and D. repleta. alpha-Amylase activity using different substrates is greater on starch than on glycogen in both species and still higher on amylose for D. virilis, the nonfungus feeder species. alpha-Amylase of D. repleta, the mycophagous species, has a better affinity to amylopectin and glycogen. Such differences in substrate specificity suggest adaptation to different resources in these species living in different habitats. Metabolic evolution seems to have occurred through a "tradeoff" between kinetic effectiveness and the nature of substrate, with a higher Vmax on amylose for D. virilis and a lower K(m) on glycogen for D. repleta.
Comp Biochem Physiol B Biochem Mol Biol 1998 Feb
PMID:Metabolic evolution in alpha-amylases from Drosophila virilis and D. repleta, two species with different ecological niches. 962 72


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