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101.
Misono H Maeda H Tuda K Ueshima S Miyazaki N Nagata S 《Applied and environmental microbiology》2005,71(8):4602-4609
An inducible phenylserine aldolase (L-threo-3-phenylserine benzaldehyde-lyase, EC 4.1.2.26), which catalyzes the cleavage of L-3-phenylserine to yield benzaldehyde and glycine, was purified to homogeneity from a crude extract of Pseudomonas putida 24-1 isolated from soil. The enzyme was a hexamer with the apparent subunit molecular mass of 38 kDa and contained 0.7 mol of pyridoxal 5' phosphate per mol of the subunit. The enzyme exhibited absorption maxima at 280 and 420 nm. The maximal activity was obtained at about pH 8.5. The enzyme acted on L-threo-3-phenylserine (Km, 1.3 mM), l-erythro-3-phenylserine (Km, 4.6 mM), l-threonine (Km, 29 mM), and L-allo-threonine (Km, 22 mM). In the reverse reaction, threo- and erythro- forms of L-3-phenylserine were produced from benzaldehyde and glycine. The optimum pH for the reverse reaction was 7.5. The structural gene coding for the phenylserine aldolase from Pseudomonas putida 24-1 was cloned and overexpressed in Escherichia coli cells. The nucleotide sequence of the phenylserine aldolase gene encoded a peptide containing 357 amino acids with a calculated molecular mass of 37.4 kDa. The recombinant enzyme was purified and characterized. Site-directed mutagenesis experiments showed that replacement of K213 with Q resulted in a loss of the enzyme activity, with a disappearance of the absorption maximum at 420 nm. Thus, K213 of the enzyme probably functions as an essential catalytic residue, forming a Schiff base with pyridoxal 5'-phosphate. 相似文献
102.
Hitoshi Ando Toshinari Takamura Naoto Matsuzawa-Nagata Seiji Nakamura Seiichiro Kurita Naoyuki Togawa Akio Fujimura 《Biochemical and biophysical research communications》2009,380(3):684-641
Recent studies have correlated metabolic diseases, such as metabolic syndrome and non-alcoholic fatty liver disease, with the circadian clock. However, whether such metabolic changes per se affect the circadian clock remains controversial. To address this, we investigated the daily mRNA expression profiles of clock genes in the liver of a dietary mouse model of non-alcoholic steatohepatitis (NASH) using a custom-made, high-precision DNA chip. C57BL/6J mice fed an atherogenic diet for 5 weeks developed hypercholesterolemia, oxidative stress, and NASH. DNA chip analyses revealed that the atherogenic diet had a great influence on the mRNA expression of a wide range of genes linked to mitochondrial energy production, redox regulation, and carbohydrate and lipid metabolism. However, the rhythmic mRNA expression of the clock genes in the liver remained intact. Most of the circadianly expressed genes also showed 24-h rhythmicity. These findings suggest that the biological clock is protected against such a metabolic derangement as NASH. 相似文献
103.
104.
Kohji Ichimori Naoto Fukuyama Hiroe Nakazawa Yasuaki Aratani Hideki Koyama Shunya Takizawa 《Free radical research》2013,47(5):481-489
Myeloperoxidase (MPO) catalyzes a nitration reaction to form nitrotyrosine in the presence of high nitrite, the metabolite of NO. Human leukocyte was shown to cause phenolic nitration using released MPO as a catalyst in the presence of nitrite. It opposes our previous finding that inhibition of MPO was essential for phenol nitration in human leukocyte study. To clarify the role of MPO, we utilized MPO-deficient human leukocytes and MPO-knockout mice. Even in the absence of exogenously added nitrite, high nitration product was observed in MPO-deficient leukocytes. In liver subjected to ischemia/reperfusion injury, a significantly higher amount of nitrotyrosine was produced in MPO-knockout mice than in normal mice. These results clearly demonstrate that MPO inhibits the accumulation of nitration products in vivo . Further experiments showed that MPO could degrade nitrotyrosine in the presence of glutathione. Thus, MPO-induced degradation of nitration products may cause the underestimation of the nitration product generated in vivo . We conclude that MPO may act predominantly to scavenge nitrotyrosine under physiological nitrite condition, and protect against injurious effect of nitrotyrosine. 相似文献
105.
106.
Morita K Flemming AJ Sugihara Y Mochii M Suzuki Y Yoshida S Wood WB Kohara Y Leroi AM Ueno N 《The EMBO journal》2002,21(5):1063-1073
Using cDNA-based array analysis combined with double-stranded RNA interference (dsRNAi), we have identified yk298h6 as a target gene of Caenorhabditis elegans TGF-beta signaling. Worms overexpressing dbl-1, a TGF-beta ligand, are 16% longer than wild type. Array analysis shows yk298h6 to be one of several genes suppressed in such worms. Disruption of yk298h6 function by dsRNAi also resulted in long worms, suggesting that it is a negative regulator of body length. yk298h6 was then mapped to, and shown to be identical to, lon-1, a known gene that affects body length. lon-1 encodes a 312 amino acid protein with a motif sequence that is conserved from plants to humans. Expression studies confirm that LON-1 is repressed by DBL-1, suggesting that LON-1 is a novel downstream component of the C.elegans TGF-beta growth regulation pathway. Consistent with this, LON-1 is expressed mainly in the larval and adult hypodermis and has dose-dependent effects on body length associated with changes in hypodermal ploidy, but not hypodermal cell proliferation. 相似文献
107.
Takashi Yamashita Naoto Tonouchi Takeshi Uozumi Teruhiko Beppu 《Molecular & general genetics : MGG》1987,210(3):462-467
Summary The aspartic protease gene of a zygomycete fungus Mucor pusillus was expressed in Saccharomyces cerevisiae under the control of the yeast GAL7 promoter. A putative preproenzyme with an NH2-terminal extension of 66 amino acids directed by the gene was processed in yeast cells and the mature enzyme, whose NH2-terminus was identical to that of the Mucor enzyme, was efficiently secreted into the medium at a concentration exceeding 150 mg/l. The enzyme secreted from the recombinant yeast was more glycosylated than the native Mucor enzyme but its enzymatic properties were almost identical with those of the native enzyme, which has been used as a milk coagulant in cheese manufacture. 相似文献
108.
Unique Induction of CA1 LTP Components After Intake of Theanine, an Amino Acid in Tea Leaves and its Effect on Stress Response 总被引:1,自引:0,他引:1
Takeda A Tamano H Suzuki M Sakamoto K Oku N Yokogoshi H 《Cellular and molecular neurobiology》2012,32(1):41-48
Theanine, γ-glutamylethylamide, is one of the major amino acid components in green tea. This study was undertaken to evaluate
the effect of theanine intake on long-term potentiation (LTP) induction at hippocampal CA1 synapses and exposure to acute
stress. Young rats were fed water containing 0.3% theanine after birth. Key findings: Serum corticosterone level was markedly
decreased by theanine intake. Because this decrease can modify synaptic plasticity, the effect of theanine intake was examined
focused on CA1 LTP induction. CA1 LTP induced by a 100-Hz tetanus for 1 s was almost the same extent in hippocampal slices
from theanine-administered rats, whereas that induced by a 200-Hz tetanus for 1 s was significantly attenuated. 2-Amino-5-phosphonovalerate
(APV), an N-methyl-d-aspartate (NMDA) receptor antagonist, significantly attenuated CA1 LTP induced by a 200-Hz tetanus in the control rats, but
not in theanine-administered rats. Interestingly, APV completely blocked CA1 LTP induced by a 100-Hz tetanus in the control
rats, while scarcely blocking it in theanine-administered rats. These results indicate that theanine intake reduces NMDA receptor-dependent
CA1 LTP, while increasing NMDA receptor-independent CA1 LTP. Furthermore, neither 100-Hz tetanus-induced LTP nor 200-Hz tetanus-induced
LTP was attenuated in theanine-administered rats after exposure to tail suspension stress, suggesting that the lack of NMDA
receptor-dependent CA1 LTP by theanine intake is involved in ameliorating the attenuation of CA1 LTP after tail suspension.
This study is the first to indicate that theanine intake modifies the mechanism of CA1 LTP induction. 相似文献
109.
Hosokawa-Muto J Ito N Yamada K Shimizu K Sugiyama M Minamoto N 《Microbiology and immunology》2006,50(3):187-196
A recombinant rabies virus carrying double glycoprotein (G) genes, R(NPMGGL) strain, was generated by a reverse genetics system utilizing cloned cDNA of the RC-HL strain, and the biological properties of the virus were compared to those of the recombinant RC-HL (rRC-HL) strain. The extents of virus growth in cultured cells and virulence for adult mice of the R(NPMGGL) strain were almost same as those of the rRC-HL strain, while G protein content of the purified R(NPMGGL) virion and G protein expression level in R(NPMGGL)-infected cells were 1.5-fold higher than those of the rRC-HL strain. As a result of serial passages of the R(NPMGGL) strain in cultured cells, the expression level of G protein in cultured cells infected with the passaged R(NPMGGL) strain was maintained and virus titers rose with adaptation to the cultured cells. Furthermore, analysis of neutralization titers in mice immunized with UVinactivated virus suggested that the R(NPMGGL) strain had higher immunogenicity than that of the rRC-HL strain. The results suggest that the R(NPMGGL) strain carrying double G genes might be a useful candidate for development of a new inactivated rabies vaccine. 相似文献
110.
Hamano K Katafuchi T Kikumoto K Minamino N 《Biochemical and biophysical research communications》2005,330(1):75-80
Calcitonin receptor-stimulating peptide-1 (CRSP-1) is a peptide recently identified from porcine brain by monitoring the cAMP production through an endogenous calcitonin (CT) receptor in the renal epithelial cell line LLC-PK(1). Here we investigated the effects of CRSP-1 on the ion transport and growth of LLC-PK(1) cells. CRSP-1 inhibited the growth of LLC-PK(1) cells with a higher potency than porcine CT. CRSP-1 enhanced the uptake of (22)Na(+) into LLC-PK(1) cells more strongly than did CT and slightly reduced the (45)Ca(2+) uptake. The enhancement of the (22)Na(+) uptake was abolished by 5-(N-ethyl-N-isopropyl) amiloride, a strong Na(+)/H(+) exchanger (NHE) inhibitor for NHE1, even at a concentration of 1x10(-8)M, although other ion transporter inhibitors did not affect the (22)Na(+) uptake. These results indicate that CRSP-1 enhances the (22)Na(+) uptake by the specific activation of NHE1. Taken together, CRSP-1 is considered to be a new regulator for the urinary ion excretion and renal epithelial cell growth. 相似文献