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Tiina Alamae - One of the best experts on this subject based on the ideXlab platform.
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Characterization of a Maltase from an Early-Diverged Non-Conventional Yeast Blastobotrys adeninivorans.
International Journal of Molecular Sciences, 2019Co-Authors: Triinu Visnapuu, Aivar Meldre, Kristina Põšnograjeva, Katrin Viigand, Karin Ernits, Tiina AlamaeAbstract:Genome of an early-diverged yeast Blastobotrys (Arxula) adeninivorans (Ba) encodes 88 glycoside hydrolases (GHs) including two α-glucosidases of GH13 family. One of those, the rna_ARAD1D20130g-encoded protein (BaAG2; 581 aa) was overexpressed in Escherichia coli, purified and characterized. We showed that Maltose, other Maltose-like substrates (maltulose, turanose, maltotriose, melezitose, malto-oligosaccharides of DP 4‒7) and sucrose were hydrolyzed by BaAG2, whereas isoMaltose and isoMaltose-like substrates (palatinose, α-methylglucoside) were not, confirming that BaAG2 is a maltase. BaAG2 was competitively inhibited by a diabetes drug acarbose (Ki = 0.8 µM) and Tris (Ki = 70.5 µM). BaAG2 was competitively inhibited also by isoMaltose-like sugars and a hydrolysis product—glucose. At high Maltose concentrations, BaAG2 exhibited transglycosylating ability producing potentially prebiotic di- and trisaccharides. Atypically for yeast maltases, a low but clearly recordable exo-hydrolytic activity on amylose, amylopectin and glycogen was detected. Saccharomyces cerevisiae maltase MAL62, studied for comparison, had only minimal ability to hydrolyze these polymers, and its transglycosylating activity was about three times lower compared to BaAG2. Sequence identity of BaAG2 with other maltases was only moderate being the highest (51%) with the maltase MalT of Aspergillus oryzae.
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maltase protein of ogataea hansenula polymorpha is a counterpart to the resurrected ancestor protein ancmals of yeast maltases and isomaltases
Yeast, 2016Co-Authors: Katrin Viigand, Karin Mardo, Anneli Aasamets, Triinu Visnapuu, Tiina AlamaeAbstract:: Saccharomyces cerevisiae maltases use Maltose, maltulose, turanose and maltotriose as substrates, isomaltases use isoMaltose, α-methylglucoside and palatinose and both use sucrose. These enzymes are hypothesized to have evolved from a promiscuous α-glucosidase ancMALS through duplication and mutation of the genes. We studied substrate specificity of the maltase protein MAL1 from an earlier diverged yeast, Ogataea polymorpha (Op), in the light of this hypothesis. MAL1 has extended substrate specificity and its properties are strikingly similar to those of resurrected ancMALS. Moreover, amino acids considered to determine selective substrate binding are highly conserved between Op MAL1 and ancMALS. Op MAL1 represents an α-glucosidase in which both maltase and isomaltase activities are well optimized in a single enzyme. Substitution of Thr200 (corresponds to Val216 in S. cerevisiae isomaltase IMA1) with Val in MAL1 drastically reduced the hydrolysis of Maltose-like substrates (α-1,4-glucosides), confirming the requirement of Thr at the respective position for this function. Differential scanning fluorimetry (DSF) of the catalytically inactive mutant Asp199Ala of MAL1 in the presence of its substrates and selected monosaccharides suggested that the substrate-binding pocket of MAL1 has three subsites (-1, +1 and +2) and that binding is strongest at the -1 subsite. The DSF assay results were in good accordance with affinity (Km ) and inhibition (Ki ) data of the enzyme for tested substrates, indicating the power of the method to predict substrate binding. Deletion of either the maltase (MAL1) or α-glucoside permease (MAL2) gene in Op abolished the growth of yeast on MAL1 substrates, confirming the requirement of both proteins for usage of these sugars. © 2016 The Authors. Yeast published by John Wiley & Sons, Ltd.
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clustering of mal genes in hansenula polymorpha cloning of the Maltose permease gene and expression from the divergent intergenic region between the Maltose permease and maltase genes
Fems Yeast Research, 2005Co-Authors: Katrin Viigand, Kersti Tammus, Tiina AlamaeAbstract:Hansenula polymorpha uses maltase to grow on Maltose and sucrose. Inspection of genomic clones of H. polymorpha showed that the maltase gene HPMAL1 is clustered with genes corresponding to Saccharomyces cerevisiae Maltose permeases and MAL activator genes orthologues. We sequenced the H. polymorpha Maltose permease gene HPMAL2 of the cluster. The protein (582 amino acids) deduced from the HPMAL2 gene is predicted to have eleven transmembrane domains and shows 39–57% identity with yeast Maltose permeases. The identity of the protein is highest with Maltose permeases of Debaryomyces hansenii and Candida albicans. Expression of the HPMAL2 in a S. cerevisiae Maltose permease-negative mutant CMY1050 proved functionality of the permease protein encoded by the gene. HPMAL1 and HPMAL2 genes are divergently positioned similarly to maltase and Maltose permease genes in many yeasts. A two-reporter assay of the expression from the HPMAL1–HPMAL2 intergenic region showed that expression of both genes is coordinately regulated, repressed by glucose, induced by Maltose, and that basal expression is higher in the direction of the permease gene.
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regulation of the hansenula polymorpha maltase gene promoter in h polymorpha and saccharomyces cerevisiae
Fems Yeast Research, 2003Co-Authors: Tiina Alamae, Katrin Viigand, Pille Parn, Helen KarpAbstract:Hansenula polymorpha is an exception among methylotrophic yeasts because it can grow on the disaccharides Maltose and sucrose. We disrupted the maltase gene (HPMAL1) in H. polymorpha 201 using homologous recombination. Resulting disruptants HP201HPMAL1Δ failed to grow on Maltose and sucrose, showing that maltase is essential for the growth of H. polymorpha on both disaccharides. Expression of HPMAL1 in HP201HPMAL1Δ from the truncated variants of the promoter enabled us to define the 5′-upstream region as sufficient for the induction of maltase by disaccharides and its repression by glucose. Expression of the Saccharomyces cerevisiae maltase gene MAL62 was induced by Maltose and sucrose, and repressed by glucose if expressed in HP201HPMAL1Δ from its own promoter. Similarly, the HPMAL1 promoter was recognized and correctly regulated by the carbon source in a S. cerevisiae maltase-negative mutant 100-1B. Therefore we suggest that the transcriptional regulators of S. cerevisiae MAL genes (MAL activator and Mig1 repressor) can affect the expression of the H. polymorpha maltase gene, and that homologues of these proteins may exist in H. polymorpha. Using the HPMAL1 gene as a reporter in a H. polymorpha maltase disruption mutant it was shown that the strength of the HPMAL1 promoter if induced by sucrose is quite comparable to the strength of the H. polymorpha alcohol oxidase promoter under conditions of methanol induction, revealing the biotechnological potential of the HPMAL1 promoter.
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cloning of maltase gene from a methylotrophic yeast hansenula polymorpha
Gene, 2001Co-Authors: Lele Liiv, Pille Parn, Tiina AlamaeAbstract:Abstract The Hansenula polymorpha maltase structural gene (HPMAL1) was isolated from a genomic library by hybridization of the library clones with maltase-specific gene probe. An open reading frame of 1695 nt encoding a 564 amino-acid protein with calculated molecular weight of 65.3 kD was characterized in the genomic DNA insert of the plasmid p51. The protein sequence deduced from the HPMAL1 exhibited 58 and 47% identity with maltases from Candida albicans and Saccharomyces carlsbergesis encoded by CAMAL2 and MAL62, respectively, and 44% identity with oligo-α-1,6-glucosidase from Bacillus cereus. The recombinant Hansenula polymorpha maltase produced in Escherichia coli hydrolyzed p-nitrophenyl-α- d -glucopyranoside (PNPG), sucrose, Maltose and α-methylglucoside and did not act on melibiose, cellobiose, trehalose and o-nitrophenyl-β- d -galactopyranoside (ONPG). The affinity of the recombinant enzyme for its substrates increased in the order Maltose
Yoshihisa Nakano - One of the best experts on this subject based on the ideXlab platform.
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triterpene glycosides of siraitia grosvenori inhibit rat intestinal maltase and suppress the rise in blood glucose level after a single oral administration of Maltose in rats
Journal of Agricultural and Food Chemistry, 2005Co-Authors: Yasushi A. Suzuki, Masaki Sugiura, Hiroshi Inui, Yuji Murata, Yoshihisa NakanoAbstract:The effect of the crude extract from Siraitia grosvenori Swingle (SG-ex) on the postprandial rise in blood glucose level was investigated. The increase in plasma glucose level in response to the oral administration of Maltose was significantly suppressed in rats when SG-ex was given orally 3 min before the Maltose administration. There was, however, no effect when glucose was administered instead, suggesting that the antihyperglycemic effect of SG-ex is elicited by inhibition of maltase in the small intestinal epithelium. In vitro, SG-ex inhibited rat small intestinal maltase. Similar effects were also observed both in vivo and in vitro when the concentrate of the sweet elements (triterpene glycosides) prepared from SG-ex was used. Furthermore, the main sweet element of SG-ex, mogroside V, and some minor elements such as mogroside IV, siamenoside I, and mogroside III also exhibited maltase inhibitory effect with IC50 values of 14, 12, 10, and 1.6 mM, respectively. These results suggest that SG-ex exerts a...
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triterpene glycosides of siraitia grosvenori inhibit rat intestinal maltase and suppress the rise in blood glucose level after a single oral administration of Maltose in rats
Journal of Agricultural and Food Chemistry, 2005Co-Authors: Yasushi A. Suzuki, Masaki Sugiura, Hiroshi Inui, Yuji Murata, Yoshihisa NakanoAbstract:The effect of the crude extract from Siraitia grosvenori Swingle (SG-ex) on the postprandial rise in blood glucose level was investigated. The increase in plasma glucose level in response to the oral administration of Maltose was significantly suppressed in rats when SG-ex was given orally 3 min before the Maltose administration. There was, however, no effect when glucose was administered instead, suggesting that the antihyperglycemic effect of SG-ex is elicited by inhibition of maltase in the small intestinal epithelium. In vitro, SG-ex inhibited rat small intestinal maltase. Similar effects were also observed both in vivo and in vitro when the concentrate of the sweet elements (triterpene glycosides) prepared from SG-ex was used. Furthermore, the main sweet element of SG-ex, mogroside V, and some minor elements such as mogroside IV, siamenoside I, and mogroside III also exhibited maltase inhibitory effect with IC50 values of 14, 12, 10, and 1.6 mM, respectively. These results suggest that SG-ex exerts anti-hyperglycemic effects in rats by inhibiting maltase activity and that these effects are at least partially exerted by its sweet elements, triterpene glycosides.
Yasushi A. Suzuki - One of the best experts on this subject based on the ideXlab platform.
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triterpene glycosides of siraitia grosvenori inhibit rat intestinal maltase and suppress the rise in blood glucose level after a single oral administration of Maltose in rats
Journal of Agricultural and Food Chemistry, 2005Co-Authors: Yasushi A. Suzuki, Masaki Sugiura, Hiroshi Inui, Yuji Murata, Yoshihisa NakanoAbstract:The effect of the crude extract from Siraitia grosvenori Swingle (SG-ex) on the postprandial rise in blood glucose level was investigated. The increase in plasma glucose level in response to the oral administration of Maltose was significantly suppressed in rats when SG-ex was given orally 3 min before the Maltose administration. There was, however, no effect when glucose was administered instead, suggesting that the antihyperglycemic effect of SG-ex is elicited by inhibition of maltase in the small intestinal epithelium. In vitro, SG-ex inhibited rat small intestinal maltase. Similar effects were also observed both in vivo and in vitro when the concentrate of the sweet elements (triterpene glycosides) prepared from SG-ex was used. Furthermore, the main sweet element of SG-ex, mogroside V, and some minor elements such as mogroside IV, siamenoside I, and mogroside III also exhibited maltase inhibitory effect with IC50 values of 14, 12, 10, and 1.6 mM, respectively. These results suggest that SG-ex exerts a...
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triterpene glycosides of siraitia grosvenori inhibit rat intestinal maltase and suppress the rise in blood glucose level after a single oral administration of Maltose in rats
Journal of Agricultural and Food Chemistry, 2005Co-Authors: Yasushi A. Suzuki, Masaki Sugiura, Hiroshi Inui, Yuji Murata, Yoshihisa NakanoAbstract:The effect of the crude extract from Siraitia grosvenori Swingle (SG-ex) on the postprandial rise in blood glucose level was investigated. The increase in plasma glucose level in response to the oral administration of Maltose was significantly suppressed in rats when SG-ex was given orally 3 min before the Maltose administration. There was, however, no effect when glucose was administered instead, suggesting that the antihyperglycemic effect of SG-ex is elicited by inhibition of maltase in the small intestinal epithelium. In vitro, SG-ex inhibited rat small intestinal maltase. Similar effects were also observed both in vivo and in vitro when the concentrate of the sweet elements (triterpene glycosides) prepared from SG-ex was used. Furthermore, the main sweet element of SG-ex, mogroside V, and some minor elements such as mogroside IV, siamenoside I, and mogroside III also exhibited maltase inhibitory effect with IC50 values of 14, 12, 10, and 1.6 mM, respectively. These results suggest that SG-ex exerts anti-hyperglycemic effects in rats by inhibiting maltase activity and that these effects are at least partially exerted by its sweet elements, triterpene glycosides.
Hiroshi Inui - One of the best experts on this subject based on the ideXlab platform.
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triterpene glycosides of siraitia grosvenori inhibit rat intestinal maltase and suppress the rise in blood glucose level after a single oral administration of Maltose in rats
Journal of Agricultural and Food Chemistry, 2005Co-Authors: Yasushi A. Suzuki, Masaki Sugiura, Hiroshi Inui, Yuji Murata, Yoshihisa NakanoAbstract:The effect of the crude extract from Siraitia grosvenori Swingle (SG-ex) on the postprandial rise in blood glucose level was investigated. The increase in plasma glucose level in response to the oral administration of Maltose was significantly suppressed in rats when SG-ex was given orally 3 min before the Maltose administration. There was, however, no effect when glucose was administered instead, suggesting that the antihyperglycemic effect of SG-ex is elicited by inhibition of maltase in the small intestinal epithelium. In vitro, SG-ex inhibited rat small intestinal maltase. Similar effects were also observed both in vivo and in vitro when the concentrate of the sweet elements (triterpene glycosides) prepared from SG-ex was used. Furthermore, the main sweet element of SG-ex, mogroside V, and some minor elements such as mogroside IV, siamenoside I, and mogroside III also exhibited maltase inhibitory effect with IC50 values of 14, 12, 10, and 1.6 mM, respectively. These results suggest that SG-ex exerts a...
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triterpene glycosides of siraitia grosvenori inhibit rat intestinal maltase and suppress the rise in blood glucose level after a single oral administration of Maltose in rats
Journal of Agricultural and Food Chemistry, 2005Co-Authors: Yasushi A. Suzuki, Masaki Sugiura, Hiroshi Inui, Yuji Murata, Yoshihisa NakanoAbstract:The effect of the crude extract from Siraitia grosvenori Swingle (SG-ex) on the postprandial rise in blood glucose level was investigated. The increase in plasma glucose level in response to the oral administration of Maltose was significantly suppressed in rats when SG-ex was given orally 3 min before the Maltose administration. There was, however, no effect when glucose was administered instead, suggesting that the antihyperglycemic effect of SG-ex is elicited by inhibition of maltase in the small intestinal epithelium. In vitro, SG-ex inhibited rat small intestinal maltase. Similar effects were also observed both in vivo and in vitro when the concentrate of the sweet elements (triterpene glycosides) prepared from SG-ex was used. Furthermore, the main sweet element of SG-ex, mogroside V, and some minor elements such as mogroside IV, siamenoside I, and mogroside III also exhibited maltase inhibitory effect with IC50 values of 14, 12, 10, and 1.6 mM, respectively. These results suggest that SG-ex exerts anti-hyperglycemic effects in rats by inhibiting maltase activity and that these effects are at least partially exerted by its sweet elements, triterpene glycosides.
Masaki Sugiura - One of the best experts on this subject based on the ideXlab platform.
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triterpene glycosides of siraitia grosvenori inhibit rat intestinal maltase and suppress the rise in blood glucose level after a single oral administration of Maltose in rats
Journal of Agricultural and Food Chemistry, 2005Co-Authors: Yasushi A. Suzuki, Masaki Sugiura, Hiroshi Inui, Yuji Murata, Yoshihisa NakanoAbstract:The effect of the crude extract from Siraitia grosvenori Swingle (SG-ex) on the postprandial rise in blood glucose level was investigated. The increase in plasma glucose level in response to the oral administration of Maltose was significantly suppressed in rats when SG-ex was given orally 3 min before the Maltose administration. There was, however, no effect when glucose was administered instead, suggesting that the antihyperglycemic effect of SG-ex is elicited by inhibition of maltase in the small intestinal epithelium. In vitro, SG-ex inhibited rat small intestinal maltase. Similar effects were also observed both in vivo and in vitro when the concentrate of the sweet elements (triterpene glycosides) prepared from SG-ex was used. Furthermore, the main sweet element of SG-ex, mogroside V, and some minor elements such as mogroside IV, siamenoside I, and mogroside III also exhibited maltase inhibitory effect with IC50 values of 14, 12, 10, and 1.6 mM, respectively. These results suggest that SG-ex exerts a...
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triterpene glycosides of siraitia grosvenori inhibit rat intestinal maltase and suppress the rise in blood glucose level after a single oral administration of Maltose in rats
Journal of Agricultural and Food Chemistry, 2005Co-Authors: Yasushi A. Suzuki, Masaki Sugiura, Hiroshi Inui, Yuji Murata, Yoshihisa NakanoAbstract:The effect of the crude extract from Siraitia grosvenori Swingle (SG-ex) on the postprandial rise in blood glucose level was investigated. The increase in plasma glucose level in response to the oral administration of Maltose was significantly suppressed in rats when SG-ex was given orally 3 min before the Maltose administration. There was, however, no effect when glucose was administered instead, suggesting that the antihyperglycemic effect of SG-ex is elicited by inhibition of maltase in the small intestinal epithelium. In vitro, SG-ex inhibited rat small intestinal maltase. Similar effects were also observed both in vivo and in vitro when the concentrate of the sweet elements (triterpene glycosides) prepared from SG-ex was used. Furthermore, the main sweet element of SG-ex, mogroside V, and some minor elements such as mogroside IV, siamenoside I, and mogroside III also exhibited maltase inhibitory effect with IC50 values of 14, 12, 10, and 1.6 mM, respectively. These results suggest that SG-ex exerts anti-hyperglycemic effects in rats by inhibiting maltase activity and that these effects are at least partially exerted by its sweet elements, triterpene glycosides.
