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Akihito Ishigami - One of the best experts on this subject based on the ideXlab platform.

  • acerola malpighia emarginata dc juice intake suppresses uvb induced skin pigmentation in smp30 gnl knockout hairless mice
    PLOS ONE, 2017
    Co-Authors: Yasunori Sato, Eriko Uchida, Takayuki Hanamura, Hitoshi Aoki, Kenichi Nagamine, Hisanori Kato, Takeshi Koizumi, Akihito Ishigami
    Abstract:

    Background/Aims Acerola (Malpighia emarginata DC.) is a fruit that is known to contain high amounts of ascorbic acid (AA) and various phytochemicals. We have previously reported that AA deficiency leads to ultraviolet B (UVB)-induced skin pigmentation in senescence marker protein 30 (SMP30)/Gluconolactonase (GNL) knockout (KO) hairless mice. The present study was undertaken to investigate the effects of acerola juice (AJ) intake on the skin of UVB-irradiated SMP30/GNL KO mice. Research design/Principal findings Five-week old hairless mice were given drinking water containing physiologically sufficient AA (1.5 g/L) [AA (+)], no AA [AA (-)] or 1.67% acerola juice [AJ]. All mice were exposed to UVB irradiation for 6 weeks. UVB irradiation was performed three times per week. The dorsal skin color and stratum corneum water content were measured every weekly, and finally, the AA contents of the skin was determined. The skin AA and stratum corneum water content was similar between the AA (+) and AJ groups. The L* value of the AA (+) group was significantly decreased by UVB irradiation, whereas AJ intake suppressed the decrease in the L* value throughout the experiment. Moreover, in the AJ group, there was a significant decrease in the expression level of dopachrome tautomerase, an enzyme that is involved in melanin biosynthesis. Conclusion These results indicate that AJ intake is effective in suppressing UVB-induced skin pigmentation by inhibiting melanogenesis-related genes.

  • Structural Basis of the c-Lactone-Ring Formation in Ascorbic Acid Biosynthesis by the Senescence Marker Protein-30/Gluconolactonase
    2016
    Co-Authors: Shingo Aizawa, Miki Senda, Ayaka Harada, Naoki Maruyama, Tetsuo Ishida, Toshiro Aigaki, Akihito Ishigami, Toshiya Senda
    Abstract:

    The senescence marker protein-30 (SMP30), which is also called regucalcin, exhibits Gluconolactonase (GNL) activity. Biochemical and biological analyses revealed that SMP30/GNL catalyzes formation of the c-lactone-ring of L-gulonate in the ascorbic acid biosynthesis pathway. The molecular basis of the c-lactone formation, however, remains elusive due to the lack of structural information on SMP30/GNL in complex with its substrate. Here, we report the crystal structures of mouse SMP30/GNL and its complex with xylitol, a substrate analogue, and those with 1,5-anhydro-D-glucitol and D-glucose, product analogues. Comparison of the crystal structure of mouse SMP30/GNL with other related enzymes has revealed unique characteristics of mouse SMP30/GNL. First, the substrate-binding pocket of mouse SMP30/GNL is designed to specifically recognize monosaccharide molecules. The divalent metal ion in the active site and polar residues lining the substrate-binding cavity interact with hydroxyl groups of substrate/product analogues. Second, in mouse SMP30/GNL, a lid loop covering the substrate-binding cavity seems to hamper the binding of L-gulonate in an extended (or all-trans) conformation; L-gulonate seems to bind to the active site in a folded conformation. In contrast, the substrate-binding cavities of the other related enzymes are open to the solvent and do not have a cover. This structural feature of mous

  • ascorbic acid deficiency affects genes for oxidation reduction and lipid metabolism in livers from smp30 gnl knockout mice
    Biochimica et Biophysica Acta, 2014
    Co-Authors: Keita Takahashi, Naoki Maruyama, Kentaro Shimokado, Yuki Kishimoto, Tomokazu Konishi, Yasunori Fujita, Masafumi Ito, Akihito Ishigami
    Abstract:

    Abstract Background We sought to elucidate the effect of an ascorbic acid (AA) deficiency on gene expression, because the water soluble antioxidant AA is an important bioactive substance in vivo. Methods We performed microarray analyses of the transcriptome in the liver from senescence marker protein-30 (SMP30)/Gluconolactonase (GNL) knockout (KO) mice, which are unable to synthesize AA in vivo. Results Our microarray analysis revealed that the AA deficiency increased gene expression related to the oxidation–reduction process, i.e., the nuclear factor, erythroid derived 2, like 2 (Nrf2) gene, which is a reactive oxygen species-sensitive transcriptional factor. Moreover, this AA deficiency increased the expression of genes for lipid metabolism including the cytochrome P450, family 7, subfamily a, polypeptide 1 (Cyp7a1), which is a late-limiting enzyme of the primary bile acid biosynthesis pathway. Although an AA deficiency increased the Cyp7a1 protein level, bile acid levels in the liver and gallbladder decreased. Since Cyp7a1 has a heme iron at the active site, AA must function as a reductant of the iron required for the continuous activation of Cyp7a1. Conclusions This experimental evidence strongly supports a role for AA in the physiologic oxidation–reduction process and lipid metabolism including bile acid biosynthesis. General significance Although many effects of AA supplementation have been reported, no microarray analysis of AA deficiency in vivo is available. Results from using this unique model of AA deficiency, the SMP30/GNL-KO mouse, now provide new information about formerly unknown AA functions that will implement further study of AA in vivo.

  • effect of ascorbic acid deficiency on catecholamine synthesis in adrenal glands of smp30 gnl knockout mice
    European Journal of Nutrition, 2014
    Co-Authors: Akiko Amano, Naoki Maruyama, Toshiro Aigaki, Makoto Tsunoda, Akihito Ishigami
    Abstract:

    The effect of an AA deficiency on catecholamine biosynthesis in adult mice in vivo is unknown. Therefore, we quantified catecholamine and the expression of catecholamine synthetic enzymes in the adrenal glands of senescence marker protein-30 (SMP30)/Gluconolactonase (GNL) knockout (KO) mice placed in an AA-deficient state. At 30 days of age, mice were divided into the following 4 groups: AA (−) SMP30/GNL KO, AA (+) SMP30/GNL KO, AA (−) wild type (WT), and AA (+) WT. The AA (+) groups were given water containing 1.5 g/L AA, whereas the AA (−) groups received water without AA until the experiment ended. In addition, all mice were fed an AA-depleted diet. Catecholamine levels were measured by a liquid chromatographic method. Tyrosine hydroxylase, dopa decarboxylase, dopamine β-hydroxylase, and phenylethanolamine N-methyltransferase mRNA expression levels were measured with the quantitative real-time polymerase chain reaction (qPCR). Tyrosine hydroxylase and dopamine β-hydroxylase protein levels were quantified by Western blot analysis. In the adrenals of AA (−) SMP30/GNL KO mice, noradrenaline and adrenaline levels decreased significantly compared to other three groups of mice, although there were no significant differences in dopamine β-hydroxylase or phenylethanolamine N-methyltransferase mRNA content. Moreover, there was no significant difference in their dopamine β-hydroxylase protein levels. On the other hand, AA depletion did not affect dopamine levels in adrenal glands of mice. An AA deficiency decreases the noradrenaline and adrenaline levels in adrenal glands of mice in vivo.

  • Structural basis of the γ-lactone-ring formation in ascorbic acid biosynthesis by the senescence marker protein-30/Gluconolactonase.
    PloS one, 2013
    Co-Authors: Shingo Aizawa, Miki Senda, Ayaka Harada, Naoki Maruyama, Tetsuo Ishida, Toshiro Aigaki, Akihito Ishigami, Toshiya Senda
    Abstract:

    The senescence marker protein-30 (SMP30), which is also called regucalcin, exhibits Gluconolactonase (GNL) activity. Biochemical and biological analyses revealed that SMP30/GNL catalyzes formation of the γ-lactone-ring of l-gulonate in the ascorbic acid biosynthesis pathway. The molecular basis of the γ-lactone formation, however, remains elusive due to the lack of structural information on SMP30/GNL in complex with its substrate. Here, we report the crystal structures of mouse SMP30/GNL and its complex with xylitol, a substrate analogue, and those with 1,5-anhydro-d-glucitol and d-glucose, product analogues. Comparison of the crystal structure of mouse SMP30/GNL with other related enzymes has revealed unique characteristics of mouse SMP30/GNL. First, the substrate-binding pocket of mouse SMP30/GNL is designed to specifically recognize monosaccharide molecules. The divalent metal ion in the active site and polar residues lining the substrate-binding cavity interact with hydroxyl groups of substrate/product analogues. Second, in mouse SMP30/GNL, a lid loop covering the substrate-binding cavity seems to hamper the binding of l-gulonate in an extended (or all-trans) conformation; l-gulonate seems to bind to the active site in a folded conformation. In contrast, the substrate-binding cavities of the other related enzymes are open to the solvent and do not have a cover. This structural feature of mouse SMP30/GNL seems to facilitate the γ-lactone-ring formation.

Yasunori Sato - One of the best experts on this subject based on the ideXlab platform.

  • acerola malpighia emarginata dc juice intake suppresses uvb induced skin pigmentation in smp30 gnl knockout hairless mice
    PLOS ONE, 2017
    Co-Authors: Yasunori Sato, Eriko Uchida, Takayuki Hanamura, Hitoshi Aoki, Kenichi Nagamine, Hisanori Kato, Takeshi Koizumi, Akihito Ishigami
    Abstract:

    Background/Aims Acerola (Malpighia emarginata DC.) is a fruit that is known to contain high amounts of ascorbic acid (AA) and various phytochemicals. We have previously reported that AA deficiency leads to ultraviolet B (UVB)-induced skin pigmentation in senescence marker protein 30 (SMP30)/Gluconolactonase (GNL) knockout (KO) hairless mice. The present study was undertaken to investigate the effects of acerola juice (AJ) intake on the skin of UVB-irradiated SMP30/GNL KO mice. Research design/Principal findings Five-week old hairless mice were given drinking water containing physiologically sufficient AA (1.5 g/L) [AA (+)], no AA [AA (-)] or 1.67% acerola juice [AJ]. All mice were exposed to UVB irradiation for 6 weeks. UVB irradiation was performed three times per week. The dorsal skin color and stratum corneum water content were measured every weekly, and finally, the AA contents of the skin was determined. The skin AA and stratum corneum water content was similar between the AA (+) and AJ groups. The L* value of the AA (+) group was significantly decreased by UVB irradiation, whereas AJ intake suppressed the decrease in the L* value throughout the experiment. Moreover, in the AJ group, there was a significant decrease in the expression level of dopachrome tautomerase, an enzyme that is involved in melanin biosynthesis. Conclusion These results indicate that AJ intake is effective in suppressing UVB-induced skin pigmentation by inhibiting melanogenesis-related genes.

  • effects of ascorbic acid deficiency on protein and lipid oxidation in livers from smp30 gnl knockout mice
    Journal of Nutritional Science and Vitaminology, 2013
    Co-Authors: Akiko Amano, Naoki Maruyama, Toshiro Aigaki, Yasunori Sato, Setsuko Handa, Yuki Kishimoto, Keita Takahashi, Akihito Ishigami
    Abstract:

    Ascorbic acid (AA) functions as an electron donor and scavenges reactive oxygen species such as superoxide, singlet oxygen, and hydroxyl radicals in vitro. However, little is known about the effect of an AA deficiency on protein and lipid oxidation levels in the liver. Therefore, we measured the levels of protein carbonyl and thiobarbituric acid reactive substances (TBARS) in livers from senescence marker protein-30 (SMP30)/Gluconolactonase (GNL) knockout (KO) mice. These mice are deficient in AA, because they lack the SMP30/GNL gene, which is essential for the biosynthesis of AA in vivo. To track the effect of an AA deficiency, at 30 d of age, mice were divided into the following four groups: AA (-) SMP30/GNL KO, AA (+) SMP30/GNL KO, AA (-) wild type (WT), and AA (+) WT. The AA (+) groups were given water containing 1.5 g/L AA, whereas the AA (-) groups received water without AA for 57 d. All mice were fed an AA-free diet. Subsequently, protein carbonyl levels in livers from AA (-) SMP30/GNL KO mice were significantly higher than those from the other three groups; however, TBARS levels were not significantly different among the four groups. Therefore, AA must act as an anti-oxidant for proteins but might not directly protect lipid oxidation in the liver.

  • hydrogen rich pure water prevents superoxide formation in brain slices of vitamin c depleted smp30 gnl knockout mice
    Biochemical and Biophysical Research Communications, 2008
    Co-Authors: Yasunori Sato, Yoshitaka Kondo, Setsuko Handa, Shizuo Kajiyama, Akiko Amano, Toru Sasaki, Ryoya Takahashi, Michiaki Fukui, Goji Hasegawa, Naoto Nakamura
    Abstract:

    Hydrogen is an established anti-oxidant that prevents acute oxidative stress. To clarify the mechanism of hydrogen’s effect in the brain, we administered hydrogen-rich pure water (H2) to senescence marker protein-30 (SMP30)/Gluconolactonase (GNL) knockout (KO) mice, which cannot synthesize vitamin C (VC), also a well-known anti-oxidant. These KO mice were divided into three groups; recipients of H2, VC, or pure water (H2O), administered for 33 days. VC levels in H2 and H2O groups were <6% of those in the VC group. Subsequently, superoxide formation during hypoxia-reoxygenation treatment of brain slices from these groups was estimated by a real-time biography imaging system, which models living brain tissues, with Lucigenin used as chemiluminescence probe for superoxide. A significant 27.2% less superoxide formed in the H2 group subjected to ischemia–reperfusion than in the H2O group. Thus hydrogenrich pure water acts as an anti-oxidant in the brain slices and prevents superoxide formation.

  • Hydrogen-rich pure water prevents superoxide formation in brain slices of vitamin C-depleted SMP30/GNL knockout mice,
    2008
    Co-Authors: Yasunori Sato, Yoshitaka Kondo, Setsuko Handa, Shizuo Kajiyama, Akiko Amano, Toru Sasaki, Ryoya Takahashi, Michiaki Fukui, Goji Hasegawa, Naoto Nakamura
    Abstract:

    Keywords: Ascorbic acid Chemiluminescence Gluconolactonase Hydrogen-rich pure water Oxidative stress ROS Senescence marker protein-30 Superoxide Vitamin C a b s t r a c t Hydrogen is an established anti-oxidant that prevents acute oxidative stress. To clarify the mechanism of hydrogen's effect in the brain, we administered hydrogen-rich pure water (H 2 ) to senescence marker protein-30 (SMP30)/Gluconolactonase (GNL) knockout (KO) mice, which cannot synthesize vitamin C (VC), also a well-known anti-oxidant. These KO mice were divided into three groups; recipients of H 2 , VC, or pure water (H 2 O), administered for 33 days. VC levels in H 2 and H 2 O groups were <6% of those in the VC group. Subsequently, superoxide formation during hypoxia-reoxygenation treatment of brain slices from these groups was estimated by a real-time biography imaging system, which models living brain tissues, with Lucigenin used as chemiluminescence probe for superoxide. A significant 27.2% less superoxide formed in the H 2 group subjected to ischemia-reperfusion than in the H 2 O group. Thus hydrogenrich pure water acts as an anti-oxidant in the brain slices and prevents superoxide formation

  • senescence marker protein 30 functions as Gluconolactonase in l ascorbic acid biosynthesis and its knockout mice are prone to scurvy
    Proceedings of the National Academy of Sciences of the United States of America, 2006
    Co-Authors: Yoshitaka Kondo, Naoki Maruyama, Morimitsu Nishikimi, Yoko Inai, Yasunori Sato, Setsuko Handa, Sachiho Kubo, Kentaro Shimokado, Sataro Goto, Akihito Ishigami
    Abstract:

    We originally identified senescence marker protein 30 (SMP30) as a distinctive protein whose expression decreases in an androgen-independent manner with aging. Here, we report its sequence homology found in two kinds of bacterial Gluconolactonases (GNLs) by using the blast search. Then, through a biochemical study, we identify SMP30 as the lactone-hydrolyzing enzyme GNL of animal species. SMP30 purified from the rat liver had lactonase activity toward various aldonolactones, such as d- and l-glucono-delta-lactone, d- and l-gulono-gamma-lactone, and d- and l-galactono-gamma-lactone, with a requirement for Zn(2+) or Mn(2+) as a cofactor. Furthermore, in SMP30 knockout mice, no GNL activity was detectable in the liver. Thus, we conclude that SMP30 is a unique GNL in the liver. The lactonase reaction with l-gulono-gamma-lactone is the penultimate step in l-ascorbic acid (AA) biosynthesis, and the essential role of SMP30 in this synthetic process was verified here by a nutritional study using SMP30 knockout mice. These knockout mice (n = 6), fed a vitamin C-deficient diet, did not thrive; i.e., they displayed symptoms of scurvy such as bone fracture and rachitic rosary and then died by 135 days after the start of receiving the deficient diet. The AA levels in their livers and kidneys at the time of death were <1.6% of those in WT control mice. In addition, by using the SMP30 knockout mouse, we demonstrate that the alternative pathway of AA synthesis involving d-glucurono-gamma-lactone operates in vivo, although its flux is fairly small.

Naoki Maruyama - One of the best experts on this subject based on the ideXlab platform.

  • Structural Basis of the c-Lactone-Ring Formation in Ascorbic Acid Biosynthesis by the Senescence Marker Protein-30/Gluconolactonase
    2016
    Co-Authors: Shingo Aizawa, Miki Senda, Ayaka Harada, Naoki Maruyama, Tetsuo Ishida, Toshiro Aigaki, Akihito Ishigami, Toshiya Senda
    Abstract:

    The senescence marker protein-30 (SMP30), which is also called regucalcin, exhibits Gluconolactonase (GNL) activity. Biochemical and biological analyses revealed that SMP30/GNL catalyzes formation of the c-lactone-ring of L-gulonate in the ascorbic acid biosynthesis pathway. The molecular basis of the c-lactone formation, however, remains elusive due to the lack of structural information on SMP30/GNL in complex with its substrate. Here, we report the crystal structures of mouse SMP30/GNL and its complex with xylitol, a substrate analogue, and those with 1,5-anhydro-D-glucitol and D-glucose, product analogues. Comparison of the crystal structure of mouse SMP30/GNL with other related enzymes has revealed unique characteristics of mouse SMP30/GNL. First, the substrate-binding pocket of mouse SMP30/GNL is designed to specifically recognize monosaccharide molecules. The divalent metal ion in the active site and polar residues lining the substrate-binding cavity interact with hydroxyl groups of substrate/product analogues. Second, in mouse SMP30/GNL, a lid loop covering the substrate-binding cavity seems to hamper the binding of L-gulonate in an extended (or all-trans) conformation; L-gulonate seems to bind to the active site in a folded conformation. In contrast, the substrate-binding cavities of the other related enzymes are open to the solvent and do not have a cover. This structural feature of mous

  • ascorbic acid deficiency affects genes for oxidation reduction and lipid metabolism in livers from smp30 gnl knockout mice
    Biochimica et Biophysica Acta, 2014
    Co-Authors: Keita Takahashi, Naoki Maruyama, Kentaro Shimokado, Yuki Kishimoto, Tomokazu Konishi, Yasunori Fujita, Masafumi Ito, Akihito Ishigami
    Abstract:

    Abstract Background We sought to elucidate the effect of an ascorbic acid (AA) deficiency on gene expression, because the water soluble antioxidant AA is an important bioactive substance in vivo. Methods We performed microarray analyses of the transcriptome in the liver from senescence marker protein-30 (SMP30)/Gluconolactonase (GNL) knockout (KO) mice, which are unable to synthesize AA in vivo. Results Our microarray analysis revealed that the AA deficiency increased gene expression related to the oxidation–reduction process, i.e., the nuclear factor, erythroid derived 2, like 2 (Nrf2) gene, which is a reactive oxygen species-sensitive transcriptional factor. Moreover, this AA deficiency increased the expression of genes for lipid metabolism including the cytochrome P450, family 7, subfamily a, polypeptide 1 (Cyp7a1), which is a late-limiting enzyme of the primary bile acid biosynthesis pathway. Although an AA deficiency increased the Cyp7a1 protein level, bile acid levels in the liver and gallbladder decreased. Since Cyp7a1 has a heme iron at the active site, AA must function as a reductant of the iron required for the continuous activation of Cyp7a1. Conclusions This experimental evidence strongly supports a role for AA in the physiologic oxidation–reduction process and lipid metabolism including bile acid biosynthesis. General significance Although many effects of AA supplementation have been reported, no microarray analysis of AA deficiency in vivo is available. Results from using this unique model of AA deficiency, the SMP30/GNL-KO mouse, now provide new information about formerly unknown AA functions that will implement further study of AA in vivo.

  • effect of ascorbic acid deficiency on catecholamine synthesis in adrenal glands of smp30 gnl knockout mice
    European Journal of Nutrition, 2014
    Co-Authors: Akiko Amano, Naoki Maruyama, Toshiro Aigaki, Makoto Tsunoda, Akihito Ishigami
    Abstract:

    The effect of an AA deficiency on catecholamine biosynthesis in adult mice in vivo is unknown. Therefore, we quantified catecholamine and the expression of catecholamine synthetic enzymes in the adrenal glands of senescence marker protein-30 (SMP30)/Gluconolactonase (GNL) knockout (KO) mice placed in an AA-deficient state. At 30 days of age, mice were divided into the following 4 groups: AA (−) SMP30/GNL KO, AA (+) SMP30/GNL KO, AA (−) wild type (WT), and AA (+) WT. The AA (+) groups were given water containing 1.5 g/L AA, whereas the AA (−) groups received water without AA until the experiment ended. In addition, all mice were fed an AA-depleted diet. Catecholamine levels were measured by a liquid chromatographic method. Tyrosine hydroxylase, dopa decarboxylase, dopamine β-hydroxylase, and phenylethanolamine N-methyltransferase mRNA expression levels were measured with the quantitative real-time polymerase chain reaction (qPCR). Tyrosine hydroxylase and dopamine β-hydroxylase protein levels were quantified by Western blot analysis. In the adrenals of AA (−) SMP30/GNL KO mice, noradrenaline and adrenaline levels decreased significantly compared to other three groups of mice, although there were no significant differences in dopamine β-hydroxylase or phenylethanolamine N-methyltransferase mRNA content. Moreover, there was no significant difference in their dopamine β-hydroxylase protein levels. On the other hand, AA depletion did not affect dopamine levels in adrenal glands of mice. An AA deficiency decreases the noradrenaline and adrenaline levels in adrenal glands of mice in vivo.

  • Structural basis of the γ-lactone-ring formation in ascorbic acid biosynthesis by the senescence marker protein-30/Gluconolactonase.
    PloS one, 2013
    Co-Authors: Shingo Aizawa, Miki Senda, Ayaka Harada, Naoki Maruyama, Tetsuo Ishida, Toshiro Aigaki, Akihito Ishigami, Toshiya Senda
    Abstract:

    The senescence marker protein-30 (SMP30), which is also called regucalcin, exhibits Gluconolactonase (GNL) activity. Biochemical and biological analyses revealed that SMP30/GNL catalyzes formation of the γ-lactone-ring of l-gulonate in the ascorbic acid biosynthesis pathway. The molecular basis of the γ-lactone formation, however, remains elusive due to the lack of structural information on SMP30/GNL in complex with its substrate. Here, we report the crystal structures of mouse SMP30/GNL and its complex with xylitol, a substrate analogue, and those with 1,5-anhydro-d-glucitol and d-glucose, product analogues. Comparison of the crystal structure of mouse SMP30/GNL with other related enzymes has revealed unique characteristics of mouse SMP30/GNL. First, the substrate-binding pocket of mouse SMP30/GNL is designed to specifically recognize monosaccharide molecules. The divalent metal ion in the active site and polar residues lining the substrate-binding cavity interact with hydroxyl groups of substrate/product analogues. Second, in mouse SMP30/GNL, a lid loop covering the substrate-binding cavity seems to hamper the binding of l-gulonate in an extended (or all-trans) conformation; l-gulonate seems to bind to the active site in a folded conformation. In contrast, the substrate-binding cavities of the other related enzymes are open to the solvent and do not have a cover. This structural feature of mouse SMP30/GNL seems to facilitate the γ-lactone-ring formation.

  • structural basis of the γ lactone ring formation in ascorbic acid biosynthesis by the senescence marker protein 30 Gluconolactonase
    PLOS ONE, 2013
    Co-Authors: Shingo Aizawa, Miki Senda, Ayaka Harada, Naoki Maruyama, Tetsuo Ishida, Toshiro Aigaki, Akihito Ishigami, Toshiya Senda
    Abstract:

    The senescence marker protein-30 (SMP30), which is also called regucalcin, exhibits Gluconolactonase (GNL) activity. Biochemical and biological analyses revealed that SMP30/GNL catalyzes formation of the γ-lactone-ring of l-gulonate in the ascorbic acid biosynthesis pathway. The molecular basis of the γ-lactone formation, however, remains elusive due to the lack of structural information on SMP30/GNL in complex with its substrate. Here, we report the crystal structures of mouse SMP30/GNL and its complex with xylitol, a substrate analogue, and those with 1,5-anhydro-d-glucitol and d-glucose, product analogues. Comparison of the crystal structure of mouse SMP30/GNL with other related enzymes has revealed unique characteristics of mouse SMP30/GNL. First, the substrate-binding pocket of mouse SMP30/GNL is designed to specifically recognize monosaccharide molecules. The divalent metal ion in the active site and polar residues lining the substrate-binding cavity interact with hydroxyl groups of substrate/product analogues. Second, in mouse SMP30/GNL, a lid loop covering the substrate-binding cavity seems to hamper the binding of l-gulonate in an extended (or all-trans) conformation; l-gulonate seems to bind to the active site in a folded conformation. In contrast, the substrate-binding cavities of the other related enzymes are open to the solvent and do not have a cover. This structural feature of mouse SMP30/GNL seems to facilitate the γ-lactone-ring formation.

Akiko Amano - One of the best experts on this subject based on the ideXlab platform.

  • effect of ascorbic acid deficiency on catecholamine synthesis in adrenal glands of smp30 gnl knockout mice
    European Journal of Nutrition, 2014
    Co-Authors: Akiko Amano, Naoki Maruyama, Toshiro Aigaki, Makoto Tsunoda, Akihito Ishigami
    Abstract:

    The effect of an AA deficiency on catecholamine biosynthesis in adult mice in vivo is unknown. Therefore, we quantified catecholamine and the expression of catecholamine synthetic enzymes in the adrenal glands of senescence marker protein-30 (SMP30)/Gluconolactonase (GNL) knockout (KO) mice placed in an AA-deficient state. At 30 days of age, mice were divided into the following 4 groups: AA (−) SMP30/GNL KO, AA (+) SMP30/GNL KO, AA (−) wild type (WT), and AA (+) WT. The AA (+) groups were given water containing 1.5 g/L AA, whereas the AA (−) groups received water without AA until the experiment ended. In addition, all mice were fed an AA-depleted diet. Catecholamine levels were measured by a liquid chromatographic method. Tyrosine hydroxylase, dopa decarboxylase, dopamine β-hydroxylase, and phenylethanolamine N-methyltransferase mRNA expression levels were measured with the quantitative real-time polymerase chain reaction (qPCR). Tyrosine hydroxylase and dopamine β-hydroxylase protein levels were quantified by Western blot analysis. In the adrenals of AA (−) SMP30/GNL KO mice, noradrenaline and adrenaline levels decreased significantly compared to other three groups of mice, although there were no significant differences in dopamine β-hydroxylase or phenylethanolamine N-methyltransferase mRNA content. Moreover, there was no significant difference in their dopamine β-hydroxylase protein levels. On the other hand, AA depletion did not affect dopamine levels in adrenal glands of mice. An AA deficiency decreases the noradrenaline and adrenaline levels in adrenal glands of mice in vivo.

  • effects of ascorbic acid deficiency on protein and lipid oxidation in livers from smp30 gnl knockout mice
    Journal of Nutritional Science and Vitaminology, 2013
    Co-Authors: Akiko Amano, Naoki Maruyama, Toshiro Aigaki, Yasunori Sato, Setsuko Handa, Yuki Kishimoto, Keita Takahashi, Akihito Ishigami
    Abstract:

    Ascorbic acid (AA) functions as an electron donor and scavenges reactive oxygen species such as superoxide, singlet oxygen, and hydroxyl radicals in vitro. However, little is known about the effect of an AA deficiency on protein and lipid oxidation levels in the liver. Therefore, we measured the levels of protein carbonyl and thiobarbituric acid reactive substances (TBARS) in livers from senescence marker protein-30 (SMP30)/Gluconolactonase (GNL) knockout (KO) mice. These mice are deficient in AA, because they lack the SMP30/GNL gene, which is essential for the biosynthesis of AA in vivo. To track the effect of an AA deficiency, at 30 d of age, mice were divided into the following four groups: AA (-) SMP30/GNL KO, AA (+) SMP30/GNL KO, AA (-) wild type (WT), and AA (+) WT. The AA (+) groups were given water containing 1.5 g/L AA, whereas the AA (-) groups received water without AA for 57 d. All mice were fed an AA-free diet. Subsequently, protein carbonyl levels in livers from AA (-) SMP30/GNL KO mice were significantly higher than those from the other three groups; however, TBARS levels were not significantly different among the four groups. Therefore, AA must act as an anti-oxidant for proteins but might not directly protect lipid oxidation in the liver.

  • ascorbic acid depletion enhances expression of the sodium dependent vitamin c transporters svct1 and svct2 and uptake of ascorbic acid in livers of smp30 gnl knockout mice
    Archives of Biochemistry and Biophysics, 2010
    Co-Authors: Akiko Amano, Naoki Maruyama, Toshiro Aigaki, Akihito Ishigami
    Abstract:

    In this study, we examined whether ascorbic acid (AA) and dehydroascorbic acid (DHA), the oxidized form of AA, levels in tissues regulate the AA transporters, sodium-dependent vitamin C transporters (SVCT) 1 and SVCT2 and DHA transporters, glucose transporter (GLUT) 1, GLUT3, GLUT4 mRNA by using senescence marker protein-30 (SMP30)/Gluconolactonase (GNL) knockout (KO) mice. These mice are incapable of synthesizing AA in vivo. AA depletion enhanced SVCT1 and SVCT2 mRNA expression in the liver and SVCT1 and GLUT4 mRNA expression in the small intestine, but not in the cerebrum or kidney. Next, we examined the actual impact of AA uptake by using primary cultured hepatocytes from SMP30/GNL KO mice. In the AA-depleted hepatocytes from SMP30/GNL KO mice, AA uptake was significantly greater than in matched cultures from wild-type mice. These results strongly affirm that intracellular AA is an important regulator of SVCT1 and SVCT2 expression in the liver.

  • hydrogen rich pure water prevents superoxide formation in brain slices of vitamin c depleted smp30 gnl knockout mice
    Biochemical and Biophysical Research Communications, 2008
    Co-Authors: Yasunori Sato, Yoshitaka Kondo, Setsuko Handa, Shizuo Kajiyama, Akiko Amano, Toru Sasaki, Ryoya Takahashi, Michiaki Fukui, Goji Hasegawa, Naoto Nakamura
    Abstract:

    Hydrogen is an established anti-oxidant that prevents acute oxidative stress. To clarify the mechanism of hydrogen’s effect in the brain, we administered hydrogen-rich pure water (H2) to senescence marker protein-30 (SMP30)/Gluconolactonase (GNL) knockout (KO) mice, which cannot synthesize vitamin C (VC), also a well-known anti-oxidant. These KO mice were divided into three groups; recipients of H2, VC, or pure water (H2O), administered for 33 days. VC levels in H2 and H2O groups were <6% of those in the VC group. Subsequently, superoxide formation during hypoxia-reoxygenation treatment of brain slices from these groups was estimated by a real-time biography imaging system, which models living brain tissues, with Lucigenin used as chemiluminescence probe for superoxide. A significant 27.2% less superoxide formed in the H2 group subjected to ischemia–reperfusion than in the H2O group. Thus hydrogenrich pure water acts as an anti-oxidant in the brain slices and prevents superoxide formation.

  • Hydrogen-rich pure water prevents superoxide formation in brain slices of vitamin C-depleted SMP30/GNL knockout mice,
    2008
    Co-Authors: Yasunori Sato, Yoshitaka Kondo, Setsuko Handa, Shizuo Kajiyama, Akiko Amano, Toru Sasaki, Ryoya Takahashi, Michiaki Fukui, Goji Hasegawa, Naoto Nakamura
    Abstract:

    Keywords: Ascorbic acid Chemiluminescence Gluconolactonase Hydrogen-rich pure water Oxidative stress ROS Senescence marker protein-30 Superoxide Vitamin C a b s t r a c t Hydrogen is an established anti-oxidant that prevents acute oxidative stress. To clarify the mechanism of hydrogen's effect in the brain, we administered hydrogen-rich pure water (H 2 ) to senescence marker protein-30 (SMP30)/Gluconolactonase (GNL) knockout (KO) mice, which cannot synthesize vitamin C (VC), also a well-known anti-oxidant. These KO mice were divided into three groups; recipients of H 2 , VC, or pure water (H 2 O), administered for 33 days. VC levels in H 2 and H 2 O groups were <6% of those in the VC group. Subsequently, superoxide formation during hypoxia-reoxygenation treatment of brain slices from these groups was estimated by a real-time biography imaging system, which models living brain tissues, with Lucigenin used as chemiluminescence probe for superoxide. A significant 27.2% less superoxide formed in the H 2 group subjected to ischemia-reperfusion than in the H 2 O group. Thus hydrogenrich pure water acts as an anti-oxidant in the brain slices and prevents superoxide formation

Takeshi Koizumi - One of the best experts on this subject based on the ideXlab platform.

  • acerola malpighia emarginata dc juice intake suppresses uvb induced skin pigmentation in smp30 gnl knockout hairless mice
    PLOS ONE, 2017
    Co-Authors: Yasunori Sato, Eriko Uchida, Takayuki Hanamura, Hitoshi Aoki, Kenichi Nagamine, Hisanori Kato, Takeshi Koizumi, Akihito Ishigami
    Abstract:

    Background/Aims Acerola (Malpighia emarginata DC.) is a fruit that is known to contain high amounts of ascorbic acid (AA) and various phytochemicals. We have previously reported that AA deficiency leads to ultraviolet B (UVB)-induced skin pigmentation in senescence marker protein 30 (SMP30)/Gluconolactonase (GNL) knockout (KO) hairless mice. The present study was undertaken to investigate the effects of acerola juice (AJ) intake on the skin of UVB-irradiated SMP30/GNL KO mice. Research design/Principal findings Five-week old hairless mice were given drinking water containing physiologically sufficient AA (1.5 g/L) [AA (+)], no AA [AA (-)] or 1.67% acerola juice [AJ]. All mice were exposed to UVB irradiation for 6 weeks. UVB irradiation was performed three times per week. The dorsal skin color and stratum corneum water content were measured every weekly, and finally, the AA contents of the skin was determined. The skin AA and stratum corneum water content was similar between the AA (+) and AJ groups. The L* value of the AA (+) group was significantly decreased by UVB irradiation, whereas AJ intake suppressed the decrease in the L* value throughout the experiment. Moreover, in the AJ group, there was a significant decrease in the expression level of dopachrome tautomerase, an enzyme that is involved in melanin biosynthesis. Conclusion These results indicate that AJ intake is effective in suppressing UVB-induced skin pigmentation by inhibiting melanogenesis-related genes.

  • Acerola (Malpighia emarginata DC.) Juice Intake Suppresses UVB-Induced Skin Pigmentation in SMP30/GNL Knockout Hairless Mice.
    Public Library of Science (PLoS), 2026
    Co-Authors: Yasunori Sato, Eriko Uchida, Takayuki Hanamura, Hitoshi Aoki, Kenichi Nagamine, Hisanori Kato, Takeshi Koizumi, Akihito Ishigami
    Abstract:

    Acerola (Malpighia emarginata DC.) is a fruit that is known to contain high amounts of ascorbic acid (AA) and various phytochemicals. We have previously reported that AA deficiency leads to ultraviolet B (UVB)-induced skin pigmentation in senescence marker protein 30 (SMP30)/Gluconolactonase (GNL) knockout (KO) hairless mice. The present study was undertaken to investigate the effects of acerola juice (AJ) intake on the skin of UVB-irradiated SMP30/GNL KO mice.Five-week old hairless mice were given drinking water containing physiologically sufficient AA (1.5 g/L) [AA (+)], no AA [AA (-)] or 1.67% acerola juice [AJ]. All mice were exposed to UVB irradiation for 6 weeks. UVB irradiation was performed three times per week. The dorsal skin color and stratum corneum water content were measured every weekly, and finally, the AA contents of the skin was determined. The skin AA and stratum corneum water content was similar between the AA (+) and AJ groups. The L* value of the AA (+) group was significantly decreased by UVB irradiation, whereas AJ intake suppressed the decrease in the L* value throughout the experiment. Moreover, in the AJ group, there was a significant decrease in the expression level of dopachrome tautomerase, an enzyme that is involved in melanin biosynthesis.These results indicate that AJ intake is effective in suppressing UVB-induced skin pigmentation by inhibiting melanogenesis-related genes