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evolution
the GNPDA2 (glucosamine-6-phosphate deaminase 2) gene is a member of glucosamine-6-phosphate (GlcN6P) deaminase subfamily
evolution
the lack of allostery as for Staphlyococcus aureus NagB has also been observed in the monomeric Staphylococcus mutans and Bacillus subtilis NagB enzymes, and supports the hypothesis that Gram-positive NagB enzymes have lost the property of allosteric regulation
evolution
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the lack of allostery as for Staphlyococcus aureus NagB has also been observed in the monomeric Staphylococcus mutans and Bacillus subtilis NagB enzymes, and supports the hypothesis that Gram-positive NagB enzymes have lost the property of allosteric regulation
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evolution
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the lack of allostery as for Staphlyococcus aureus NagB has also been observed in the monomeric Staphylococcus mutans and Bacillus subtilis NagB enzymes, and supports the hypothesis that Gram-positive NagB enzymes have lost the property of allosteric regulation
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malfunction
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mutant parasites lacking GND are unable to grow in medium containing amino sugars as sole carbohydrate source and rapidly loose viability, concomitant with the hyper-accumulation of hexosamine-phosphates. Expression of native GND, but not a cytosolic form of GND, in DELTAgnd parasites restored hexosamine-dependent growth, indicating that toxicity is due to depletion of glycosomal pools of ATP. Promastigote and amastigote stages of the DELTAgnd mutant are unable to replicate within macrophages and were either completely cleared or exhibited reduced lesion development in highly susceptible Balb/c mice
malfunction
depletion of GFAT1 reduces the cellular pool of UDP-GlcNAc and hyaluronan synthesis, while simultaneous blocking of both isozymes GNPDA1 and GDPDA2 exerts opposite effects, indicating that in standard culture conditions keratinocyte GNPDAs mainly catalyze the reaction from GlcN6P back to Fru6P. When hexosamine biosynthesis is blocked by GFAT1 siRNA, the effect by GNPDAs is reversed, now catalyzing Fru6P towards GlcN6P, likely in an attempt to maintain UDPGlcNAc content. Silencing of these enzymes also changes the gene expression of related enzymes: GNPDA1 siRNA induces GFAT2 which is hardly measurable in these cells under standard culture conditions, GNPDA2 siRNA increases GFAT1, and GFAT1 siRNA increases the expression of hyaluronan synthase 2 (HAS2). Silencing of GFAT1 stimulates GNPDA1 and GDPDA2, and inhibites cell migration. The multiple delicate adjustments of these reactions demonstrate the importance of hexosamine biosynthesis in cellular homeostasis, known to be deranged in diseases like diabetes and cancer. GNPDA1 siRNA, while ineffective by itself, could largely prevent the influence of mannose on UDP-GlcNAc and hyaluronan synthesis, thus raising GNPDA1 as a specific candidate for the target of mannose. The finding that GNPDA1 siRNA does not counteract the mannose-induced depletion of cell surface hyaluronan suggests that in addition to GNPDA1 mannose may target cell surface receptor activity
malfunction
depletion of GFAT1 reduces the cellular pool of UDP-GlcNAc and hyaluronan synthesis, while simultaneous blocking of both isozymes GNPDA1 and GDPDA2 exerts opposite effects, indicating that in standard culture conditions keratinocyte GNPDAs mainly catalyze the reaction from GlcN6P back to Fru6P. When hexosamine biosynthesis is blocked by GFAT1 siRNA, the effect by GNPDAs is reversed, now catalyzing Fru6P towards GlcN6P, likely in an attempt to maintain UDPGlcNAc content. Silencing of these enzymes also changes the gene expression of related enzymes:GNPDA1 siRNA induces GFAT2 which is hardly measurable in these cells under standard culture conditions, GNPDA2 siRNA increases GFAT1, and GFAT1 siRNA increases the expression of hyaluronan synthase 2 (HAS2). Silencing of GFAT1 stimulates GNPDA1 and GDPDA2, and inhibites cell migration. The multiple delicate adjustments of these reactions demonstrate the importance of hexosamine biosynthesis in cellular homeostasis, known to be deranged in diseases like diabetes and cancer
malfunction
two single-nucleotide polymorphisms of the GNPDA2 gene are significantly associated with body weight and a number of fatness traits in chicken, overview
metabolism
controlling the biosynthetic and degradative pathways of amino sugar metabolism is important in all organisms to avoid loss of nitrogen and energy via a futile cycle of synthesis and breakdown. The enzyme glucosamine-6P deaminase (NagB) is central to this control, and N-acetylglucosamine-6P is the key signaling molecule regulating amino sugar utilization in Escherichia coli
metabolism
distinct contributions of glucosamine-6-phosphate (GlcN6P):glutamine-fructose-6-phosphate aminotransferases (GFAT1 and 2) and glucosamine-6-phosphate deaminases (GNPDA1 and 2) isozymes to the UDP-GlcNAc pool of cultured keratinocytes, and their consequences to the hyaluronan synthesis, one of the cellular processes most dependent on cytosolic UDP-GlcNAc supply, and to cell proliferation and migration, overview
metabolism
distinct contributions of glucosamine-6-phosphate (GlcN6P):glutamine-fructose-6-phosphate aminotransferases (GFAT1 and 2) and glucosamine-6-phosphate deaminases (GNPDA1 and 2)isozymes to the UDP-GlcNAc pool of cultured keratinocytes, and their consequences to the hyaluronan synthesis, one of the cellular processes most dependent on cytosolic UDP-GlcNAc supply, and to cell proliferation and migration, overview
metabolism
NanE, GlcNAc-6P epimerase, and the uridylylated PII protein allosterically activate NagB by direct protein-protein interactions. NanE is essential for N-acetylneuraminic acid (NANA) and N-acetylmannosamine (ManNAc) utilization, and the PII protein is known to be a central metabolic nitrogen regulator. Regulatory links between carbon and nitrogen metabolism are important for adaptation of metabolism to different growth conditions. Regulatory interdependence between different metabolic pathways
physiological function
hGNPDA1 can be important for the maintenance of an adequate level of the pool of the UDP-GlcNAc6P, the N-acetylglucosylaminyl donor for many reactions in the cell
physiological function
NagB, a glucosamine 6-phosphate deaminase in Escherichia coli, is essential for amino sugar utilization and is known to be allosterically regulated by N-acetylglucosamine 6-phosphate (GlcNAc-6P) and the histidine-phosphorylatable phosphocarrier protein, HPr. Specific physiological functions for the regulation of NagB by its three protein activators
physiological function
the enzyme glucosamine-6P deaminase (NagB) is required for growth on both GlcN and GlcNAc. It is an allosteric enzyme in Escherichia coli, displaying sigmoid kinetics with respect to its substrate, GlcN6P, and is allosterically activated by GlcNAc6P. The high concentration of GlcN6P, accompanied by the small increase in GlcNAc6P, drives Escherichia coli NagB (NagBEc) into its high activity state, as observed during growth on GlcN
physiological function
the GNPDA2 gene encodes an allosteric enzyme of glucosamine 6-phosphate deaminase (GlcN6P), which can catalyzes the reversible conversion of D-glucosamine 6-phosphate into D-fructose-6-phosphate and ammonium. The GNPDA2 gene has a potential role in the regulation of body weight, fat and energy metabolism in chicken
additional information
possible functional significance of the C-terminal extension of hGNPDA1 isozyme, which is not present in isoform 2
additional information
possible functional significance of the C-terminal extension of hGNPDA1 isozyme, which is not present in isoform 2
additional information
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possible functional significance of the C-terminal extension of hGNPDA1 isozyme, which is not present in isoform 2