The role of pH decrease in tofu-like precipitate formation using magnesium chloride.

Uncertainty surrounds the role of pH in tofu-like precipitate (TLP) formation using MgCl. In this study, to clarify the role of MgCl-induced pH decrease in TLP formation, the protein concentration in the supernatant, weight of wet precipitate, and the solubility in 2 M urea at constant pH (6.5 or 6.

Chemical structure and gelation characteristics of a purified gel derived from sword beans ().

Herein, a new method was developed to obtain a crude extract from sword beans at a higher extraction efficiency. The crude extract formed a gel at 8 °C, which melted at 70 °C, and lyophilization of the purified gel produced a powder that could be dissolved in distilled water at a concentration of 7 % (w/w) or less. A 3 % powder solution gelled at 12 °C and melted at 60 °C.

Development of Tofun: A new sweet confection made from soymilk and honey.

Tofu, a common part of the Asian diet, is soft, making it a good candidate for developing foods for people with dysphagia. Honey can coagulate soymilk proteins due to high levels of gluconic acid. In the present study, we aimed to investigate the soymilk-coagulating ability of 19 honey varieties to develop a soft sweet for people with dysphagia.

Direct comparison of the tofu-like precipitate formation by adding different coagulants: magnesium chloride and glucono-δ-lactone.

Tofu is produced by adding a coagulant such as MgCl and glucono-δ-lactone (GDL) in soymilk. However, the molecular mechanism of tofu formation by adding these coagulants has been compared between the results obtained under different conditions. In this study, the formation of a tofu-like precipitate (TLP) by adding GDL was directly compared with that formed by adding MgCl under the same conditions except for the coagulants.

Honey-mediated aggregation of soymilk proteins.

Gluconic acid, the major organic acid in honey, is a partial hydrolysate of glucono-δ-lactone, typically used as a coagulant in preparing tofu. The present study aimed to examine the coagulation potential of five different types of honey at different concentrations, upon addition to soymilk. In some samples, aggregates formed in the upper layer at a higher honey concentration, while in others, aggregates precipitated at an intermediate honey concentration.

Structural transitions of sword bean canavalin in response to different salt concentrations.

Canavalin is the major storage protein in sword beans () and belongs to the 7S seed globulin class. Canavalin solubility can be reversibly altered via the addition of MgCl and CaCl at different concentrations; specifically, it is insoluble at lower concentrations and soluble at higher concentrations. However, the addition of NaCl does not induce the insolubilization of canavalin.

Divalent magnesium cation concentrations determine the formation of tofu-like precipitates with differing urea solubilities.

Different coagulant concentrations can induce urea-soluble precipitates (USPs) and urea-insoluble precipitates (UIPs) during tofu-like precipitate formation. In this study, MgCl concentration-dependent changes in USPs were quantified using a method based on urea solubility differences in order to investigate the factors affecting USP versus UIP formation. The addition of various Mg salts revealed that anions influence the solubility of proteins in both USPs and UIPs.

Sword bean variants and different pretreatments influence protein extraction and protein properties.

Two variants of the sword bean (Canavalia gladiata), namely the white sword bean (WSB) and the red sword bean (RSB), are known. The MgCl concentration-dependent canavalin solubility showed different behavior among the extracts from distinct beans prepared by distinct pretreatments. Pretreatment and bean selection are important factors for use in food chemical and biochemical experiments.

A crude sword bean (Canavalia gladiata) extract is gelated by cooling.

White sword bean (Canavalia gladiata) seeds have the potential to be utilized in the manufacturing of processed foods owing to their high protein and carbohydrate content. Our previous reports explored the use of the sword bean as a source of food materials by preparing extracts in distilled water. In the present study, we found that one such extract can be gelated by cooling.

Espresso coffee foam delays cooling of the liquid phase.

Espresso coffee foam, called crema, is known to be a marker of the quality of espresso coffee extraction. However, the role of foam in coffee temperature has not been quantitatively clarified. In this study, we used an automatic machine for espresso coffee extraction.

Reversible changes of canavalin solubility controlled by divalent cation concentration in crude sword bean extract.

Canavalin is a vicilin-class (7S) storage protein found in sword bean (Canavalia gladiata). Our previous report indicated that canavalin is precipitated by the addition of 20 mM MgCl to crude sword bean extract. Here, we examined the solubility changes induced by the addition of Mg and Ca at various concentrations.

Trans 18-carbon monoenoic fatty acid has distinct effects from its isomeric cis fatty acid on lipotoxicity and gene expression in Saccharomyces cerevisiae.

Epidemiological studies have suggested that an excess intake of trans-unsaturated fatty acids increases the risk of coronary heart disease. However, the mechanisms of action of trans-unsaturated fatty acids in eukaryotic cells remain unclear. Since the budding yeast Saccharomyces cerevisiae can grow using fatty acids as the sole carbon source, it is a simple and suitable model organism for understanding the effects of trans-unsaturated fatty acids at the molecular and cellular levels.

Precipitation of sword bean proteins by heating and addition of magnesium chloride in a crude extract.

Sword bean (Canavalia gladiata) seeds are a traditional food in Asian countries. In this study, we aimed to determine the optimal methods for the precipitation of sword bean proteins useful for the food development. The soaking time for sword beans was determined by comparing it with that for soybeans.

Detection of an interaction between prion protein and neuregulin I-β1 by fluorescence resonance energy transfer analysis.

Cellular prion protein (PrP) copurifies with neuregulin type I-β1 (NRG I-β1), but no interaction has been detected by a general immunoprecipitation study. We speculate that PrP interacts with NRG I-β1. Here, the interaction of PrP with NRG I-β1 was detected by measuring fluorescence resonance energy transfer (FRET) between enhanced blue (EBFP) and enhanced green (EGFP) fluorescent protein-fusion proteins.

Role of calcium-binding sites in calcium-dependent membrane association of annexin A4.

Annexin A4 (Anx4) is a cytosolic calcium-binding protein with four repeat domains, each containing one calcium-binding site (CBS). The protein interacts with the phospholipid membrane through the CBS-coordinated calcium ion, although the role of each CBS in the calcium-dependent association is unclear. To determine the role of each CBS, 15 CBS-abolished variants were produced in various combinations by substitution of a calcium-liganding residue on each CBS by Ala.

Initiation of protein association in tofu formation by metal ions.

Magnesium and calcium ions are important factors in making tofu. However, the molecular role of these ions remains unclear in tofu formation. We have previously shown that magnesium chloride concentration-dependent produced silken tofu-like (SP) and regular tofu-like (RP) precipitates, but was an inconsequential factor for the retention of tofu.

Magnesium chloride concentration-dependent formation of tofu-like precipitates with different physicochemical properties.

A wet precipitate is generated in the process of making tofu by adding a coagulant to the basic soymilk ingredient. We investigated the magnesium chloride concentration-dependent change in the precipitate weight. The wet precipitate weight dramatically increased following a short plateau phase at a low concentration of magnesium chloride.

High hatching rates after cryopreservation of hydrated cysts of the brine shrimp A. franciscana.

Cysts of Artemia franciscana are known to be extremely tolerant to UV and ionizing radiation, hypoxia, dryness, osmotic pressure, and temperatures. However, when cysts are hydrated, their resistance to extreme environmental conditions is markedly reduced, and they subsequently enter a developmental sequence. The hatching rate of hydrated cysts declined when they were rapidly frozen after a short period of hydration but slow freezing improved hatching rates after 6-h hydration (1.

Production of a recombinant full-length prion protein in a soluble form without refolding or detergents.

Recombinant prion protein has been produced in insoluble form and refolded following solubilization with denaturants. It is, however, preferable to use a soluble recombinant protein prepared without artificial solubilization. In this study, a soluble recombinant prion protein was produced in Escherichia coli cells by coexpression of neuregulin I-β1 and purified to high purity.

Network structure and forces involved in perilla globulin gelation: comparison with sesame globulin.

Scanning electron micrographs show that perilla globulin gel had a finer network structure than sesame α-globulin gel. The effects of various reagents on the gel formation and solubility of perilla and sesame gels were compared. The contribution of disulfide bonds to the formation and stability of perilla gel was greater than to sesame gel, despite having the same subunit structure.

Subunit structure and functional properties of the predominant globulin of perilla (Perilla frutescens var. frutescens) seeds.

Approximately 40% of defatted perilla seeds consists of proteins which are primarily composed of globulin (84%). The amino acid profile of perilla proteins demonstrated balanced amounts of all essential amino acids, except for lysine. The molecular mass of the predominant globulin was estimated to be 340 kDa by gel filtration.

Crystal structures of sodium-bound annexin A4.

Annexin A4 (Anx4) possesses four repeat domains with one Ca(2+)-binding site (CBS) in each domain. In this study, we resolved two crystal structures of the Na(+)-bound form at high resolution (1.58 and 1.

Production of a soluble recombinant prion protein fused to blue fluorescent protein without refolding or detergents in Escherichia coli cells.

The physiological function of prion proteins (PrP) remains unclear. To investigate the physiological relevance of PrP, we constructed a fusion protein of PrP with enhanced blue fluorescent protein (PrP-EBFP) to quantify the interaction of PrP with other molecules. Production of soluble PrP-EBFP was achieved by lowering the expression temperature in Escherichia coli (E.

Chipping at large, potent human T-cell leukemia virus type 1 protease inhibitors to uncover smaller, equipotent inhibitors.

The human T-cell leukemia virus type 1 (HTLV-I) causes adult T-cell leukemia and several severe chronic diseases. HTLV-I protease (PR) inhibition stops the propagation of the virus. Herein, truncation studies were performed on potent octapeptidic HTLV-I PR inhibitor KNI-10161 to derive small hexapeptide KNI-10127 with some loss in activity.

Identification of peptidomimetic HTLV-I protease inhibitors containing hydroxymethylcarbonyl (HMC) isostere as the transition-state mimic.

Towards the development of chemotherapy for the infection by human T-cell leukemia virus type I (HTLV-I), we have established evaluation systems for HTLV-I protease (PR) inhibitors using both recombinant and chemically synthesized HTLV-I PRs. Newly synthesized substrate-based inhibitors containing hydroxymethylcarbonyl (HMC) isostere showed potent anti-HTLV-I PR activity.