• The Korean Journal of Physiology and Pharmacology
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• v.6 no.2
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• pp.101-107
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• 2002

In the present study, the postnatal developmental changes in the expressional levels of cardiac sarcoplasmic reticulum (SR) $Ca^{2+}$ regulatory proteins, i.e. $Ca^{2+}-ATPase,$ phospholamban, and $Ca^{2+}$ release channel, were investigated. Both SR $Ca^{2+}-ATPase$ and phospholamban mRNA levels were about 35% of adult levels at birth and gradually increased to adult levels. Protein levels of both SR $Ca^{2+}-ATPase$ and phospholamban, which were measured by quantitative immunoblotting, were closely correlated with the mRNA levels. The initial rates of $Ca^{2+}$ uptake at birth were about 40% of adult rates and also increased gradually during the myocardial development. Consequently, the relative phospholamban/$Ca^{2+}-ATPase$ ratio was 1 in developmental hearts. $Ca^{2+}$ release channel (ryanodine receptor) mRNA was about $50{\sim}60%$ at birth and increased gradually to adult level throughout the postnatal rat heart development. $^3[H]ryanodine$ binding increased gradually during postnatal myocardial development, which was closely correlated with ryanodine mRNA expression levels during the development except the ryanodine mRNA level at birth. These findings indicate that cardiac SR $Ca^{2+}-ATPase,$ phospholamban, and $Ca^{2+}$ release channel are expressed coordinately, which may be necessary for intracellular $Ca^{2+}$ regulation during the rat heart development.

• Proceedings of the Korean Biophysical Society Conference
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• 2003.06a
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• pp.53-53
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• 2003

Calumenin was previously identified as a high affinity Ca$\^$2+/ binding protein in mouse cardiac sarcoplasmic reticulum (SR). For the present study, a 48 kDa skeletal homologue of calumenin was identified by sucrose-density gradient of rabbit skeletal SR membranes, concanavalin A treatment, 2D-gel electrophoresis, $\^$45/Ca$\^$2+/ overlay, Stains-all staining, and MALDI-TOF analysis. We attempted to clone the skeletal calumenin by RT-PCR based on mouse cardiac and human calumenin sequences. The deduced amino acid sequence (315 residues) of the skeletal calumenin showed high identity to mouse cardiac calumenin (90％). As seen in the cardiac calumenin, the deduced sequence contains a 19 amino acid N-terminal signal sequence and a HDEF C-terminal sequence, a putative retrieval signal to ER. Also, the skeletal calumenin contains one N-glycosylation site, three PKC phosphorylation sites, eight casein kinase 2 phosphorylation sites, and 6 EF-hand domains. GST-calumenin showed a conformational change and increased mobility in the presence of Ca$\^$2+/ in SDS-PAGE. Three calumenin interacting proteins (ryanodine receptor 1, glycogen phosphorylase, and phosphofructo kinase) were identified by pull-down assay with GST-calumenin and solubilized SR. All the interactions were Ca$\^$2+/dependent. The present results suggest that calumenin plays an important role in Ca$\^$2+/ homeostasis of muscle cells.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.19 no.4
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• pp.333-338
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• 1986

Compositions of protein and amino acid in the muscle of crucian carp, Carassius carassius, and snakehead, Channa argus, were determined by amino acid autoanalyzer, and the protein subunits composed of sarcoplasmic and myofibrillar proteins were also analyzed by sodium dodecylsulfate (SDS) polyacrylamide gel electrophoresis. The crucian carp muscle contained about $14.7\%$ of protein, and the protein was composed of $32.6\%$ in sarcoplasmic, $62.0\%$ in myofibrillar, $4.9%$ in alkali soluble and $0.6\%$ in stroma protein. The snakehead muscle, on the other hand, contained about $16.1\%$ of protein, and $30.7\%,\;64.1\%,\;4.7\%\;and\;0.4\%$ in the above order. The sarcoplasmic and myofibrillar proteins were composed of 10 and 19 subunits respectively, in the crucian carp, and 12 and 18 subunits in the snakehead. The total amino acid compositions in the muscle of the crucian carp and snakehead were found to be very similar except lysine and glutamic acid. The major amino acids of their muscle protein were lysine, glutamic acid, arginine and aspartic acid in order. In free amino acid content of the crucian carp, histidine occupied $52\%$ of the total free amino acid, and glutamic acid, glycine and taurine did $85\%$ in case of snakehead.

• Food Science of Animal Resources
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• v.41 no.6
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• pp.997-1011
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• 2021

The processing characteristics of freeze-dried pork powder as raw meat for comminuted meat products were compared with those of freeze-thawed pork. The tertiary structural properties, oxidation, and solubility of proteins in the freeze-dried pork powder were investigated. In addition, the properties of the emulsion gels manufactured with freeze-dried pork powder (GFD) and freeze-thawed pork (GFT) at 1.5% and 2.0% NaCl were evaluated. The surface hydrophobicity and intrinsic tryptophan fluorescence intensity of myofibrillar proteins between the freeze-dried pork powder and freeze-thawed pork were similar. However, freeze-dried pork powder had higher carbonyl compounds and lower solubility of sarcoplasmic and myofibrillar proteins than freeze-thawed pork (p<0.05). GFD had higher cooking loss than GFT in 2.0% NaCl, and lower hardness and a^* value of GFD were observed regardless of NaCl level (p<0.05). Moreover, GFD had higher malondialdehyde content than GFT at the two NaCl concentrations (p<0.05). Therefore, our study demonstrated that freeze-dried pork powder has lower functional properties than freeze-thawed pork as raw meat for comminuted meat products.

• BMB Reports
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• v.47 no.2
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• pp.69-79
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• 2014

$Ca^{2+}$ release from intracellular stores and influx from extracellular reservoir regulate a wide range of physiological functions including muscle contraction and rhythmic heartbeat. One of the most ubiquitous pathways involved in controlled $Ca^{2+}$ influx into cells is store-operated $Ca^{2+}$ entry (SOCE), which is activated by the reduction of $Ca^{2+}$ concentration in the lumen of endoplasmic or sarcoplasmic reticulum (ER/SR). Although SOCE is pronounced in non-excitable cells, accumulating evidences highlight its presence and important roles in skeletal muscle and heart. Recent discovery of STIM proteins as ER/SR $Ca^{2+}$ sensors and Orai proteins as $Ca^{2+}$ channel pore forming unit expedited the mechanistic understanding of this pathway. This review focuses on current advances of SOCE components, regulation and physiologic and pathophysiologic roles in muscles. The specific property and the dysfunction of this pathway in muscle diseases, and new directions for future research in this rapidly growing field are discussed.

• Proceedings of the Korean Biophysical Society Conference
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• 2003.06a
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• pp.66-66
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• 2003

In skeletal muscle cells, depolarization of the transverse tubules (T-tubules) results in Ca$\^$2+/ release from the sarcoplasmic reticulum (SR), leading to elevated cytoplasmic Ca$\^$2+/ and muscle contraction. This process has been known as excitation-contraction coupling (E-C coupling). Several proteins, such as the ryanodine receptor (RyR), triadin, junctin, and calsequestrin (CSQ), have been identified to be involved in the Ca$\^$2＋/ release process. However, the molecular interactions between the SR proteins have not been resolved. In the present study, the mechanisms of interaction between RyRl and triadin have been studied by in vitro protein binding and $\^$45/Ca$\^$2+/ overlay assays. Our data demonstrate that the intraluminal loop II of RyR1 binds to triadin in Ca$\^$2+/-independent manner. Moreover, we could not find any Ca$\^$2+/ binding sites in the loop II region. GST-pull down assay revealed that a KEKE motif of triadin, which was previously identified as a CSQ binding site (Kobayasi et al.,2000 JBC) was also a binding site for RyR1. Our results suggest that the intraluminal loop II of RyR could participate in the RyR-mediated Ca$\^$2+/ release process by offering a direct binding site to luminal triadin.

• The Journal of Korean Physical Therapy
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• v.19 no.4
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• pp.1-14
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• 2007

Background: It is generally accepted that skeletal muscle contraction is triggered by nerve impulse and intracellular $Ca^{2+}\;([Ca^{2+}]_i)$ released from intracellular $Ca^{2+}$ stores such as sarcoplasmic reticulum (SR). Specifically, this process, called excitation-contraction (E-C) coupling, takes place at intracellular junctions between the plasma membrane, the transverse (T) tubule L-type $Ca^{2+}$ channel (dihydropyridine-sensitive L-rype $Ca^{2+}$ channel, DHPR, also called tetrads), and the SR $Ca^{2+}$ release channel (ryanodine-sensitive $Ca^{2+}$ release channel, RyR, also called feet) of internal $Ca^{2+}$ stores in skeletal muscle cells. Furthermore, it has been reported that the $Ca^{2+-}$ dependent and -independent contraction determine the expression of skeletal muscle genes, thus providing a mechanism for tightly coupling the extent of muscle contraction to regulation of muscle plasticity-related excitation-transcription (E-T) coupling. Purpose: Expression and activity of plasticity-associated enzymes in gastrocnemius muscle strips have not been well studied, however. Methods: Therefore, in this study the expression and phosphorylation of E-C and E-T coupling-related mediators such as protein kinases, ROS(reactive oxygen species)- and apoptosis-related substances, and others in gastrocnemius muscles from rats was examined. Results: I found that expression and activity of MAPKs (mitogen-activated protein kinases, ERK1/2, p38MAPK, and SAPK/JNK), apoptotic proteins (cleaved caspase-3, cytochrome c, Ref-1, Bad), small GTP-binding proteins (RhoA and Cdc42), actin-binding protein (cofilin), PKC (protein kinase C) and $Ca^{2+}$ channel (transient receptor potential channel 6, TRPC6) was observed in rat gastrocnemius muscle strips. Conclusion: These results suggest that MAPKs, ROS- and apoptosis-related enzymes, cytoskeleton-regulated proteins, and $Ca^{2+}$ channel may in part functionally import in E-C and E-T coupling from rat skeletal muscles.

• Proceedings of the Korean Biophysical Society Conference
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• 2001.06a
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• pp.67-67
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• 2001

Our previous studies showed that the relaxation defect of diabetic heart was due to the changes in the expressional levels of SR $Ca^{2＋}$-ATPase and PLB. In the diabetic heart contractile abnormalities were also observed, and one of the mechanisms for these changes could include alterations in the expression and/or activity levels of various $Ca^{2＋}$ regulatory proteins involving cardiac contraction.(omitted)

• Applied Biological Chemistry
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• v.14 no.2
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• pp.165-169
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• 1971

From both breast and leg muscle of 12 week-old broiler chicken held for aging in slushed ice and dry chilling at $33-35^{\circ}F$., myosin, actomyosin and other nitrogenous fractions were extracted with KCl-phosphate buffer for various periods from 1 hr. to 25 hr. post-mortem. The changes in extractable nitrogen occurred mainly as a result of decrease in extractability of myosin and to some extent, increase in extractability of actomyosin. Changes in stroma, sarcoplasmic and NPN fractions were small. Myosin extractability decreased rapidly during the first 3 hr. post-mortem and then reduced Continuously in both leg muscle and breast muscle during wet chilling. The decrease of myosin extractability in leg muscle was much more than that in breast muscle, and then the extractability increased after 17 hr. post-mortem in dry chilling. Actomyosin was extracted at low consistent level in wet chilling, while it increased considerably after 17 hr. post-mortem in dry chilling. The tendency was similar in both breast and leg muscle.

• Food Science of Animal Resources
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• v.31 no.5
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• pp.663-667
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• 2011

This study was performed to measure the angiotensin I-converting enzyme (ACE) inhibitory activity of peptide extracts derived from the enzymatic proteolysis of Hanwoo Musculus longissimus (M. longissimus) during cold storage. Thermolysin (80 ppm, w/w) and protease type XIII (100 ppm, w/w) were injected separately or in combination for the enzymatic proteolysis of sarcoplasmic and myofibrillar proteins prior to storage at $5^{\circ}C$ (T1) or at $-1^{\circ}C$ (T2) in a chilling room for 9 days. Beef injected with thermolysin (E2) and thermolysin+protease type XIII (E3) showed a significantly higher degree of hydrolysis at both storage temperatures (p<0.05). During the storage period, T1E2 at day 6 and T1E3 at day 9 showed the strongest ACE inhibitory activity with sarcoplasmic and myofibrillar protein proteolysates. Macromolecules greater than 10,000 Da were removed by ultra filtration, and the filtrates were separated into fractions using gel filtration. Five and three major fractions were collected from S-T1E2-6 and M-T1E3-9 extracts, respectively, and the $4^{th}$ fraction of the S-T1E2-6 extracts showed the highest ACE inhibitory rate of $61.96{\pm}7.41%$.