Laboratory of Nutrition Chemistry

Kyoto, Japan

Laboratory of Nutrition Chemistry

Kyoto, Japan
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Miyake Y.,Laboratory of Enzyme Chemistry | Tsuzuki S.,Laboratory of Nutrition Chemistry | Mochida S.,Laboratory of Nutrition Chemistry | Fushiki T.,Laboratory of Nutrition Chemistry | Inouye K.,Laboratory of Enzyme Chemistry
Biochimica et Biophysica Acta - Proteins and Proteomics | Year: 2010

Matriptase is a type II transmembrane serine protease containing one potential site for asparagine-linked glycosylation (N-glycosylation) on the catalytic domain (Asn772). It has been found that the activation of matriptase zymogen occurs via a mechanism requiring its own activity and that the N-glycosylation site is critical for the activation. The present study aimed to determine the underlying reasons for the site requirement using Madin-Darby canine kidney cells stably expressing recombinant variants of rat matriptase. A full-length variant with glutamine substitution at Asn772 appeared to be unable to undergo activation because of its catalytic incompetence (i.e., decreased availability of the soluble catalytic domain and/or of the correctly folded domain). This was evidenced by the observations that (i) a recombinant catalytic domain of matriptase with glutamine substitution at the site corresponding to matriptase Asn772 [N772Q-CD-Myc(His)6] was not detected in the medium conditioned by transfected cells but was on the cell surface and (ii) purified N772Q-CD-Myc(His)6 exhibited markedly reduced activity toward a peptide substrate. It is concluded that N-glycosylation site at Asn772 of matriptase is required for the zymogen activation because it plays an important role in rendering this protease catalytically competent in the cellular environment. © 2009 Elsevier B.V. All rights reserved.

Haramizu S.,Laboratory of Nutrition Chemistry | Kawabata F.,Laboratory of Nutrition Chemistry | Masuda Y.,Laboratory of Nutrition Chemistry | Ohnuki K.,Laboratory of Nutrition Chemistry | And 3 more authors.
Bioscience, Biotechnology and Biochemistry | Year: 2011

Enhancing energy expenditure and reducing energy intake are both crucial for weight control. Capsinoids, which are non-pungent capsaicin analogs, are known to suppress body fat accumulation and reduce body weight by enhancing energy expenditure in both mice and humans. However, it is poorly understood whether the suppression of body fat accumulation by capsinoids has an advantage over dietary restriction. This study shows that the oxygen consumption was increased in mice administered with capsinoids but not in dietaryrestricted mice, although there was a similar suppression of body fat accumulation in both groups. The weight rebound was more notable in the dietaryrestricted mice than in the mice administered with capsinoids. These results indicate that suppressing body fat accumulation by capsinoids was more beneficial than a restricted diet for maintaining body weight.

Mori N.,Laboratory of Nutrition Chemistry | Kawabata F.,Laboratory of Nutrition Chemistry | Matsumura S.,Laboratory of Nutrition Chemistry | Hosokawa H.,Kyoto University | And 3 more authors.
American Journal of Physiology - Regulatory Integrative and Comparative Physiology | Year: 2011

The transient receptor potential (TRP) channel family is composed of a wide variety of cation-permeable channels activated polymodally by various stimuli and is implicated in a variety of cellular functions. Recent investigations have revealed that activation of TRP channels is involved not only in nociception and thermosensation but also in thermoregulation and energy metabolism. We investigated the effect of intragastric administration of TRP channel agonists on changes in energy substrate utilization of mice. Intragastric administration of allyl isothio-cyanate (AITC; a typical TRPA1 agonist) markedly increased carbohydrate oxidation but did not affect oxygen consumption. To examine whether TRP channels mediate this increase in carbohydrate oxidation, we used TRPA1 and TRPV1 knockout (KO) mice. Intra-gastric administration of AITC increased carbohydrate oxidation in TRPA1 KO mice but not in TRPV1 KO mice. Furthermore, AITC dose-dependently increased intracellular calcium ion concentration in cells expressing TRPV1. These findings suggest that AITC might activate TRPV1 and that AITC increased carbohydrate oxidation via TRPV1. © 2011 the American Physiological Society.

Saito T.,T. Hasegawa Co. | Shiibashi H.,T. Hasegawa Co. | Myoga H.,T. Hasegawa Co. | Haraguchi K.,T. Hasegawa Co. | And 6 more authors.
Nippon Shokuhin Kagaku Kogaku Kaishi | Year: 2014

Driedbonito (Katsuobushi) is widely used in Japanese cuisine as a traditional Japanese seasoning. The aroma plays an important role in the flavor of the cuisine. The role of dried bonito aroma was demonstrated in experiments with mice: the aroma of a supercritical carbon dioxide extract of dried bonito stimulated the reward system, consistent with the presentation of highly palatable food. The current research revealed the potent odor-active volatiles of supercritical carbon dioxide dried bonito extract (Bonito CO2 Ex). Aroma extract dilution analysis (AEDA) of Bonito CO2 Ex identified ten odorants as potent odor-active volatiles with the highest flavor dilution (FD) factor of 15625 and 3 125: 2-methoxyphenol showeda FD factor of 15625, followedby 2-methoxy-5-methylphenol, 2, 6-dimethoxyphenol, 4-ethyl-2,6-dimethoxyphenol, 2,6-dimethylphenol, 2-methoxy-4-propylphenol, 4-hydroxy-3-methoxy benzaldehyde, 4-hydroxy-2,5-dimethyl-3(2H)-furanone, (2E,7Z)-trans-4,5-epoxydeca-2,7-dienal and (4Z,7Z)-trideca-4,7-dienal (TDD) with a FD factor of 3125. This was the first time TDD was identified in a food. Sensory evaluation of the aroma reconstitutions of Bonito CO2 Ex revealedthat TDD contributed significantly to the Bonito CO2 Ex aroma. Furthermore, the efficacy of additional TDD to enhance the pleasant flavor of dried bonito broth was confirmedby sensory evaluation conductedby an experiencedchef of traditional Japanese cuisine. Copyright © 2014, Japanese Society for Food Science and Technology.

Shirouchi B.,Laboratory of Nutrition Chemistry | Nakamura Y.,Laboratory of Nutrition Chemistry | Furukawa Y.,Laboratory of Nutrition Chemistry | Shiraishi A.,Laboratory of Nutrition Chemistry | And 3 more authors.
Cardiovascular Drugs and Therapy | Year: 2012

Purpose Ezetimibe has been shown to inhibit dietary cholesterol absorption in animal models and humans, but studies on lymphatic lipid transport have not yet been performed. Rats subjected to permanent lymph duct cannulation were used to investigate the effects of ezetimibe on lipid transport. Methods Rats were fed diets with and without ezetimibe (5.0 mg/kg), and their lymph was collected after feeding to quantify lymphatic lipid levels. Total cholesterol content in the intestinal mucosa was also measured. Results Rats that consumed ezetimibe had significantly lower lymphatic total cholesterol transport with the reduction of esterified cholesterol transport. According to the calculation based on cholesterol consumption, ezetimibe reduced the total cholesterol lymphatic recovery rate by 54 %. We also determined that ezetimibe significantly reduced the total cholesterol content in the intestinal mucosa. Conclusion This is the first direct evidence that ezetimibe inhibits esterified but not free cholesterol lymphatic transport in thoracic duct-cannulated rats. The results also indicate that ezetimibe is not involved in the lymphatic transport of triacylglycerols, phospholipids, or a-tocopherol. © Springer Science+Business Media, LLC 2012.

Matsumura S.,Laboratory of Nutrition Chemistry | Yoneda T.,Laboratory of Nutrition Chemistry | Aki S.,Laboratory of Nutrition Chemistry | Eguchi A.,Laboratory of Nutrition Chemistry | And 4 more authors.
Physiology and Behavior | Year: 2010

We investigated substances that induce a rewarding effect during the postingestive process using the conditioned place preference (CPP) test. Although mice showed high affinity for a low-energy fat substitute-sorbitol fatty acid esters and low-concentration linoleic acid solution-they did not exhibit a place preference toward a voluntary intake of fat substitute in the CPP test. However, during a conditioning session of CPP that involved intragastric administration of corn oil immediately before the intake of the fat substitute, the test mice displayed a place preference. Similarly, intragastric administration of glucose, galactose, and dextrin also induced CPP; however, fructose, mannose, and a nonmetabolized carbohydrate did not. These results suggest that administration of corn oil and glucose has the same postingestive effect with regard to inducing CPP and that the structural specificity of carbohydrates influences the postingestive effect. © 2009 Elsevier Inc. All rights reserved.

Takai M.,Laboratory of Nutrition Chemistry | Tsuzuki S.,Laboratory of Nutrition Chemistry | Matsuno Y.,Laboratory of Nutrition Chemistry | Kozai Y.,Laboratory of Nutrition Chemistry | And 4 more authors.
Bioscience, Biotechnology and Biochemistry | Year: 2013

CD36 binds oxidized low-density lipoprotein (oxLDL). A synthetic peptide comprising amino-acid residues 149-168 of mouse CD36 was recently found to bind fluorescence-labeled oxLDL particles. Based on our oxLDL-binding analysis of various synthetic CD36 peptides, we suggest that not only hydrophilic residues (e.g., Lys164 and Lys166) but also hydrophobic ones (e.g., Phe153, Leu158, and Leu161) are critical to binding.

Sakamoto K.,Laboratory of Nutrition Chemistry | Okahashi T.,Laboratory of Nutrition Chemistry | Matsumura S.,Laboratory of Nutrition Chemistry | Okafuji Y.,Laboratory of Nutrition Chemistry | And 4 more authors.
Bioscience, Biotechnology and Biochemistry | Year: 2015

Rodents show a stronger preference for fat than sucrose, even if their diet is isocaloric. This implies that the preference mechanisms for fat and sucrose differ. To compare the contribution of the opioid system to the preference of fat and sucrose, we examined the effects of mu-, delta-, kappa-, and non-selective opioid receptor antagonists on the preference of sucrose and fat, assessed by a twobottle choice test and a licking test, in mice naïve to sucrose and fat ingestion. Administration of nonselective and mu-selective opioid receptor antagonists more strongly inhibited the preference of fat than sucrose. While the preference of fat was reduced to the same level as water by the antagonist administration that of sucrose was still greater than water. Our results suggest that the preference of fat relies strongly on the opioid system, while that of sucrose is regulated by other mechanisms in addition to the opioid system. © 2014 Japan Society for Bioscience, Biotechnology, and Agrochemistry.

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