• Food Science of Animal Resources
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• v.43 no.6
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• pp.1031-1043
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• 2023

The purpose of this study was to investigate the functional properties of salt-soluble proteins obtained from Protaetia brevitarsis (PB) and Tenebrio molitor (TM) larvae, the interaction between these proteins and pork myofibrillar protein (MP) in a gel system. The gel properties of salt-soluble protein extracts showed that the PB had a higher viscosity than the TM protein. However, the TM protein had higher gel strength compared with the PB protein. The gelation characteristics of the pork MP gel systems added with lyophilized insect salt-soluble protein powder showed to decrease slightly viscosity compared with MP alone. Adding the TM or PB protein powder did not affect the pork MP's hydrophobicity and sulfhydryl group levels. Furthermore, the protein bands of the MP did not change with the type or amount of insect salt-soluble protein. The cooking yields of the pork MP gels containing PB or TM protein powder were higher than those without insect protein. Regardless of the type of insect salt-soluble protein added, the pork MP's gel strength decreased. Furthermore, as the level of insect powder increased, the surface protein structure became rough and porous. The results demonstrated that proteins extracted from PB and TM larvae interfered with the gelation of pork MP in a gel system.

• Journal of Microbiology and Biotechnology
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• v.33 no.12
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• pp.1671-1680
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• 2023

The gluten protein content in whole-wheat flour is low, which affects the elasticity and viscosity of the dough. Enzymatic modification of the protein may result in a network that mimics gluten, which plays an important role in the processing of whole-wheat foods. In this study, the effects of Halomonas alkaliantartica laccase (LacHa) on the quality parameters of whole-wheat bread were investigated. The optimum dosage of LacHa was 4 U/100 g of whole-wheat flour. At this dosage, whole-wheat bread exhibited the best specific volume and optimum texture parameters. Laccase also extended the storage duration of whole-wheat bread. We analyzed the micro-structure of the dough to determine its gluten-free protein extractable rate and free sulfhydryl group content, and verify that LacHa mediates cross-linking of gluten-free proteins. The results demonstrated that the cross-linking of gluten-free protein by LacHa improves the texture of whole-wheat bread. As a flour improver, LacHa has great developmental and application potential in baked-food production.

• The Korean Journal of Pharmacology
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• v.24 no.2
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• pp.179-187
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• 1988

Verapamil, tetrodotoxin and tetraethylammonium chloride in the stated amount did not affect the $Na^{++}$ induced $Ca^{++}$ release. $Cd^{++}$ and $Zn^{++}$ significantly inhibited the $Na^{++}$ induced $Ca^{++}$ release. $Mn^{++}$ also inhibited $Na^+-Ca^{++}$ exchange. $Cd^{++}$ inhibited $Na^+-Ca^{++}$ exchange noncompetitively with an apparent inhibition constant (Ki) of $100\;{\mu}M$. $Cd^{++}$ caused loss of sulfhydryl group, whereas $Zn^{++}$ did not show any significant effect. $Cd^{++}$ and $Zn^{++}$ effectively inhibited $Na^+-Ca^{++}$ ATPase and slightly inhibited $Ca^{++}-Mg^{++}$ ATPase. Carbonyl cyanide chlorophenylhydrazone, 2,4-dinitrophenol and sodium arsenate stimulated the $Na^{++}$ induced $Ca^{++}$ release. Dibucaine and oligomycin slightly inhibited it. The results suggest that the $Na^+-Ca^{++}$ exchange on the synaptosomal plasma membrane may be not accomplished by ion channels. The $Na^+-Ca^{++}$ exchange is sensitively inhibited by $Cd^{++}$ and this transport process appears to be partially regulated by sulfhydryl groups of the synaptosomal plasma membrane. It is also postulated that $Na^+-Ca^{++}$ exchange is suppressed during the phosphorylation reaction of protein component on the neuronal membrane.

• The Korean Journal of Pharmacology
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• v.21 no.2
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• pp.79-89
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• 1985

Mechanism of calcium transport inhibition of cardiac sarcoplasmic reticulum (SR) by oxygen free radicals was examined. Effects of oxygen free radicals generated by xanthine/xanthine oxidase (X/XO) system on isolated porcine ventricle SR were studied with respect to its calcium binding, lipid peroxidation, SH-group content and alteration of membrane protein components. The results are as follows. 1) Calcium binding of isolated SR was markedly inhibited by X/XO. 2) During the incubation of sarcoplasmic reticulum with xanthine/xanthine oxidase, there were marked inclose in lipid peroxidation and reduction of SH-group content. 3) An antioxidant, p-phenylenediamine effectively prevented the lipid peroxidation but partially prevented the calcium binding inhibition of X/XO treated SR. 4) The reduction of SH-group content of SR treated with X/XO was partially prevented by p-phenylendiamine. 5) When modifying SH-group of SR by treatment with DTNB, the inhibition of calcium binding activity was partially prevented. 6) On gel-permeation chromatography of X/XO-treated sarcoplasmic reticulum, there was an increase of small molecular weight products, probably protein degradation products. 7) Semicarbazide, which prevents the cross-linking reaction of protein components, did not affect the calcium binding inhibition of X/XO-treated SR. From these results, it is suggested that the inhibition of calcium binding of SR by oxygen free radicals results from the consequence of multiple changes of SR components, which are lipid peroxidation, SH-group oxidation and degradation of protein components.

• Food Science of Animal Resources
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• v.38 no.2
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• pp.291-301
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• 2018

To shorten the production cycle of Zaodan, this study first pickled Zaodan by a novel technology - vacuum decompression technology. Vacuum decompression technology could reduce the pickling time of Zaodan from 20 wk to about 9 wk. The protein content, moisture and pH of the Zaodan egg white gradually decreased with a concomitant increase in salt during the pickling process. The total sulfhydryl group (SH) group content of the egg white proteins was increased to $2.43{\times}10^{-3}mol/L$ after being pickled for 30 d, whereas the content of disulphide bonds (SS) was reduced to $23.35{\times}10^{-3}mol/L$. The surface hydrophobicity was lowest after pickling for 30 d. In addition, great changes occurred in the secondary structure of the egg white proteins after pickling for 20 d. The disappearance of ovomucin was noticeable based on sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis.

• Bulletin of the Korean Chemical Society
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• v.32 no.1
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• pp.286-290
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• 2011

Ginsenoside Rg3 was reported to have important biological activities. We demonstrate conjugation and quantification procedures of ginsenoside Rg3 to gold nanoparticles for future biological and medical applications. Ginsenoside Rg3 was conjugated to spherical gold nanoparticles using a bifunctional heptaethylene glycol linker. The sulfhydryl group of heptaethylene glycol was adsorbed onto gold nanoparticles, and carboxylic acid end of heptaethylene glycol was bonded through a hydroxyl group of Rg3 via ester bond formation. The conjugation of Rg3 was characterized with various spectroscopic techniques, high resolution-transmission electron microscopy, and using Rg3 monoclonal antibody. The Rg3- functionalized gold nanoparticles were $4.7{\pm}1.0$ nm in diameter with a surface charge of -4.12 mV. The total number of Rg3 molecules conjugated to a 3.6 mL solution of gold nanoparticle was determined to be $9.5{\times}10^{14}$ corresponding to ~6 molecules of Rg3/gold nanoparticle. These results suggest that ginsenoside Rg3 is successfully conjugated to gold nanoparticles via heptaethylene glycol linker. The quantification was performed by using Rg3 monoclonal antibody without interference of gold's intrinsic color.

• The Korean Journal of Physiology
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• v.24 no.2
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• pp.345-352
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• 1990

To determine the role of sulfhydryl group in transport of organic ions across the basolateral membrane of renal proximal tubules, effect of p-chloromercuribenzoic acid (PCMB) on the transport of tetraethylammonium (TEA) and p-aminohippurate (PAH) was studied in rabbit renal cortical slices. PCMB caused irreversible inhibition of TEA and PAH uptake in a dose-dependent manner, with $I_{50}$ value (concentration for 50% inhibition) of $30\;{\mu}M$ for TEA and $75\;{\mu}M$ for PAH. Kinetic analysis of TEA and PAH uptakes showed that PCMB decreased Vmax $(62.35\;vs.\;28.32\;n\;mole/g{\cdot}min\;fur\;TEA:\;385.24\;vs.\;170.36\;n\;mole/g{\cdot}min\;for\;PAH)$ without changing Km. The inhibitory action of PCMB on TEA and PAH uptakes was independent of pH of the pretreatment medium. The inhibitory effect of PCMB on the uptake of TEA or PAH was prevented by dithiothreitol, but not by the substrate. PCMB inhibited Na-K-ATPase activity in a dose-dependent manner with $I_{50}$ value of $50\;{\mu}M$, which is similar to those for TEA and PAH uptake. These results suggest that PCMB inhibits the transport of organic cations and anions in the renal basolateral membrane by directly affecting the SH-group in the transporter molecules or secondly by altering the Na-K-ATPase activity.

• The Korean Journal of Physiology
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• v.7 no.2
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• pp.9-16
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• 1973

In view of the recent knowledge on the radioprotective action of reduced glutathione (GSH), the present study was designed the elucidate the effect of some concentrations of GSH on the levels of intrinsic non-protein sulfhydryl (NP-SH) and non-protein disulfide (NP-SS) of the mouse liver incubated at 4, 25 and 37C in vitro, respectively. The liver slice of the mouse was incubated at 4, 25 and 37C in the medium composed of 100 ml of Krebs-Ringer phosphate buffer (KRP) with the addition of 10, 20 and 30 mg of GSH, respectively. Measurement of NP-SH and NP-SS was made at 5, 30 and 60 min during the course of the incubation, and the results were compared with the controls which were incubated only in KRP medium, and the normal. The results thus obtained are summarized as follows: 1. When the mouse liver slice was incubated at 4C, the values of both NP-SH and NP-SS of the control and the group where 10 mg of GSH was added to the incubation medium were similar to those of the normal group, and the increase of NP-SH and NP-SS with the increased concentrations of GSH was not prominent. 2. When the liver slice was incubated in the concentrations of GSH 20 mg/100 ml KRP and GSH 30 mg/100 ml KRP at 25 C, the rate of increase of both NP-SH and NP-SS was proportional to the increase of GSH concentration. In the group where 10 mg of GSH was added to the incubation medium, the value of NP-SH and NP-SS reached the highest value at 30 min, but a tendency of decrease was observed at 60 min. 3. The rate of increase of NP-SH and NP-SS of the liver was most marked of all the group. studied when the incubation temperatuse was elevated to 37C, and the increase was proportional to the concentration of GSH and the incubation time.

• International Journal of Oral Biology
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• v.33 no.3
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• pp.117-123
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• 2008

Reactive oxygen species (ROS) are toxic agents that may be involved in various neurodegenerative diseases. Recent studies indicate that ROS can act as modulators of neuronal activity, and are critically involved in persistent pain primarily through spinal mechanisms. In the present study, whole cell patch clamp recordings were carried out to investigate the effects of tert-buthyl hydroperoxide (t-BuOOH), an ROS, on neuronal excitability and the mechanisms underlying changes of membrane excitability. In current clamp condition, application of t-BuOOH caused a reversible membrane depolarization and firing activity in substantia gelatinosa (SG) neurons. When slices were pretreated with phenyl-N-tert-buthylnitrone (PBN) and ascorbate, ROS scavengers, t-BuOOH failed to induce membrane depolarization. However, isoascorbate did not prevent t-BuOOH-induced depolarization, suggesting that the site of ROS action is intracellular. The t-BuOOH-induced depolarization was not blocked by pretreatment with dithiothreitol (DTT), a sulfhydryl-reducing agent. The membrane-impermeant thiol oxidant 5,5-dithiobis 2-nitrobenzoic acid (DTNB) failed to induce membrane depolarization, suggesting that the changes of neuronal excitability by t-BuOOH are not caused by the modification of extrathiol group. The t-BuOOH-induced depolarization was suppressed by the phospholipase C (PLC) blocker U-73122 and inositol triphosphate ($IP_3$) receptor antagonist 2-aminoethoxydiphenylbolate (APB), and after depletion of intracellular $Ca^{2+}$ pool by thapsigargin. These data suggest that ROS generated by peripheral nerve injury can induce central sensitization in spinal cord, and t-BuOOH-induced depolarization may be regulated by intracellular $Ca^{2+}$ store mainly via $PLC-IP_3$ pathway.

• The Journal of Internal Korean Medicine
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• v.19 no.1
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• pp.431-441
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• 1998

This study was undertaken to determine whether Buthus exract(BTE) affects Na^+-K^+-ATPase$ activity of nervous tissues. The enzym activity was measured in synaptosomal fraction prepared from rabbit brain cortex. Na^+-K^+-ATPase$ activity was inhibited by BTE over concentration range of 0.05-0.5% in a dose-dependent manner. The enzyme activity was increased by an increase in $Na^+$ concentration from 5 to 100mM, $K^+$ concentration from 0.5 to 10mM, and $Mg^{2+}$ concentration from 0.2 to 5mM. These changes in ion concentrations did not produce any effect on the inhibitory effect of BTE on $Na^+-K^+-ATPase$ activity. An increase in ATP concentration from 0.1 to 3mM caused an increase in the enzyme activity. The inhibition of the enzyme activity by BTE were not different between two ATP concentrations. A sulfhydryl group protector DTT prevented PCMB-induced inhibition of $Na^+-K^+-ATPase$ activity, but the BTE-induced inhibition was not altered by DTT. The inhibition of enzyme activity by combination of ouabain and BTE was not different from that by Buthus alone. These results suggest that Buthus exerts inhibitory effect on $Na^+-K^+-ATPase$ activity in cerebral synaptosomes, and the action mechansim is similar to that of ouabain.