• Proceedings of the Korean Society for Food Science of Animal Resources Conference
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• 2002.05a
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• pp.140-140
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• 2002

• The Korean Journal of Pharmacology
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• v.8 no.2
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• pp.55-61
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• 1972

Superprecipitation of actomyosin has been considered to be an in vitro model of the muscle contraction. The superprecipitation and ATPase activity (which supplies the energy for contraction) are influenced by several factors which are the large amount of changes in ionic strength, Mg and ATP concentrations. But those behaviors are found to be promptly influenced by the change in a small range of calcium concentration which can be controlled by the cellular function of muscle physiologically only in the presence of the modullatory proteins, tropomyosin and troponin. In order to elucidate the precise roles of calcium in the muscle contraction and relaxation, the effects of calcium on the actin- myosin interaction was observed in the presence of tropomyosin and troponin using the superprecipitation system. The results are summarized as follows: 1. EGTA (glycol ether diaminetetraacetic acid)prolonged the initiation of the superprecipitation of natural actomyosin. 2. Superprecipitation curve was declined by adding EGTA at the time when tile curve reached the half- maximum. The degree of declining was proportional to the amount of EGTA added. Especially, upon adding 0.25 mM EGTA the curve was lowered to the level before the protein superprecipitated. But addition of EGTA did not affect the curve after attaining the maximum. 3. Superprecipitation of Perry myosin B was not affected by EGTA added both before and during the course of the reaction. 4. Tropomyosin did not change the response of Perry myosin B to EGTA added at any time of the reaction. 5. Troponin also did not change the response of Perry myosin B to EGTA. 6. Both tropomyosin and troponin together rendered the Perry myosin B to obtain the same response as natural actomyosin to EGTA. 7. It was concluded that actin-myosin interaction was influenced by the minute change of calcium concentration only in the presence of both tropomyosin and troponin. We could reproduce the contraction and relaxation of the muscle in vitro under the presence of ATP by changing the calcium concentration.

• Korean Journal of Food Science and Technology
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• v.20 no.3
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• pp.371-379
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• 1988

To investigate on the biochemical characteristics of myofibrillar proteins between cold(pollack, salmon) and warm current fish (yellow corbina, shark), myofibrils and actomyosin were prepared, and their biological activities, effect of temperature on the myofibrillar ATPase activities and SDS-polyacrylamide gel electrophoretic patterns of myofibrils were compared. SDS-polyacrylamide gel electrophoretic analysis showed that electrophoretic patterns of myofibril vary from fish to fish. Difference in KCl concentration dependency of myofibrillar ATPase activities and ATPase activity- pH curve were found among fish species. Myofibrillar proteins from cold current fish showed higher specific activity at low temperature $(5^{\circ}C-10^{\circ}C)$ than those from warm current fish.

• Korean Journal of Poultry Science
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• v.14 no.2
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• pp.137-143
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• 1987

This study was carried out to compare the changes in the extractability, biological activity, and solubility of myofibrillar proteins and actomyosins during storage period at 4$^{\circ}C$ and -20$^{\circ}C$in pectoral. and leg muscle of broiler meat. 1. The results obtained are as fellows ; The extractabilities of myofibrillar proteins in pectoral and leg muscle were increased gradually to 7-days during storage at 4$^{\circ}C$ and decreased slightly during frozen storage at -20$^{\circ}C$. The extractabilities of actomyosins in pectoral and legmuscle were not greatly changed during cold storage and decreased gradually during frozen storage. 2. The Ca$\^$2+/-ATP ase activities of myofibrillar proteins in the both muscles were not greatly changed to 7-days during cold storage, and in the case of frozen storage, those were highest on the 2nd week, thereafter decreased with storage period. The Ca$\^$2+/-ATPase activities of actomyosins in pectoral and leg muscle were decreased sightly only frist day during cold storage and decreased gently during frozen storage. 3. Myofibrillar proteins in the both muscles were solubilized completely at 0.20M KCl in fresh meat, at 0.25M (pectoral) and 0.30M KCl (leg) in the cold storage, and at 0.30M KCl in the frozen storage. Actomyosins of both muscles were solubilized completely at 0.40M KCl in fresh meat, cold and frozen storage.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.6
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• pp.823-828
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• 1998

The objective of this study is to investigate cryoprotective effects of corn starch enzyme hydrolysates of nonsweet and low-calories on denaturation of frozen fish protein. The cryoprotective effects of were examined in Alaska pollack actomyosin solution by changes in SDS-PAGE pattern, solubility, and $Ca^{2+}$-ATPase activity. When samples stored for 0 and 30 days were compared on SDS-PAGE patterns, severe changes in all bands were shown on the control sample regardless of storage temperature, especially in myosin heavy chain (MHC). Not much difference no appeared the electrophoretic pattern in case of the samples containing sucrose at any storage temperature during 30 days of storage. The cryoprotective effect of the hydrolysates were markedly dependant on storage temperature and no MHC band was found in the samples stored at $-5^{\circ}C$. The SDS-PAGE patterns of sample stored at $-20^{\circ}C$, however, completely maintained after 30 days or storage. When the samples were stored at $-5^{\circ}C$, the solubility of the sample containing sucrose was retained at $90\%$ after 30 days of storage, whereas dramatically decreased in other samples. The samples including sucrose, D.E. 10, 15, and 20 revealed $90\%$ in solubility when stored at $-20^{\circ}C$. The tendency of remaining $Ca^{2+}$-ATPase activity was almost shown the same as that of solubility.

• BMB Reports
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• v.51 no.4
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• pp.182-187
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• 2018

In carcinoma, cancer-associated fibroblasts participate in force-mediated extracellular matrix (ECM) remodeling, consequently leading to invasion of cancer cells. Likewise, the ECM remodeling actively occurs in glioblastoma (GBM) and the consequent microenvironmental stiffness is strongly linked to migration behavior of GBM cells. However, in GBM the stromal cells responsible for force-mediated ECM remodeling remain unidentified. We show that tumor-associated mesenchymal stem-like cells (tMSLCs) provide a proinvasive matrix condition in GBM by force-mediated ECM remodeling. Importantly, CCL2-mediated Janus kinase 1 (JAK1) activation increased phosphorylation of myosin light chain 2 in tMSLCs and led to collagen assembly and actomyosin contractility. Collectively, our findings implicate tMSLCs as stromal cells providing force-mediated proinvasive ECM remodeling in the GBM microenvironment, and reminiscent of fibroblasts in carcinoma.

• Korean Journal of Food Science and Technology
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• v.6 no.4
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• pp.199-208
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• 1974

An attempt was made to study on new method for the extraction of the regulatory proteins from myofibrils, and the procedures for the preparation of desensitized actomyosin and for complete extraction of troponin-tropomyosin complex were developed. When myofibrils were treated through the procedures developed in this study, actomyosin obtained had no Ca-sensitivity, indicating that Ca-sensitizing protein factor had been removed completely from myofibril. Consequently, it was concluded that the procedures developed in this study were convenient to test whether Ca-sensitizing proteins has been removed or not. When Mg-activated ATPase activity of myofibril were measured, the myofibrillar ATPase turned into the actomyosin type ATPase with the progress of the treatment. This result was interpreted to show that the regulatory proteins of the myofibril seems to play a cementing role on the structure of myofibril. When supernatant containing the regulatory proteins were fractionated with $(NH_4)_2SO_4$ saturation solution, regulatory proteins, ${\alpha}-actinin$ and troponia-tropomyosin complex, could be obtained and they showed their typical phyoislogical activity which modify the actin-myosin interaction. The amount of troponin-tropomyosin complex in myofibril was 72 mg per g myofibril. This result was in good agreement with the results reported by many investigators, and therefore it was concluded that our procedures for the extraction of troponin-tropomyosin complex were desirable to study on the quantitative analysis of troponin-tropomyosin complex.

• Journal of the Korean Applied Science and Technology
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• v.24 no.4
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• pp.362-368
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• 2007

To study the relationship between elementary biochemical states and structural states of the actomyosin crossbridges in muscle, the effects of binding of MgADP to myosin heads in the rigor muscle were examined by X-ray diffraction using synchrotron radiation. X-ray diffraction studies have been made to investigate the effects of binding of ADP on the structure of glycerinated rabbit skeletal muscle in the rigor state. The intensity increase was accompanied by a slight but distinct decrease in the 5.9 am layer-line intensity close to the meridian. These results strongly suggest that myosin heads altered their attached conformation in the proximal end toward the plane perpendicular to the fiber axis when MgADP was bound to them. We found that the intensity of the 14.5 nm-based meridional reflections increase by 20-50% when MgADP was added to the rigor muscle in the presence of hexokinase and myokinase inhibitor.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2002.10a
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• pp.112-113
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• 2002

생선회의 품질을 결정하는 중요한 요인은 씹힘성(촉감)으로, 생선회의 단단함(toughness)은 어종, 원료어의 신선도, 조리 후의 저장조건 및 치사방법 등에 따라 달라진다. 어육의 단단함은 생선회의 맛에 직결되어 육질이 단단한 어종일수록 양질의 횟감으로 선호되기 때문에 육질을 개선하기 위한 일련의 연구가 진행되고 있다. 즉, 운동사육에 의하여 근육의 장력을 발생시키는 방법, 사육수온을 변화시키는 방법, 한약재를 사료에 투여하여 육중의 결합조직의 함량을 증대시키는 방법 및 절식사육에 의하여 양식어의 육질을 개선하는 방법 등으로, 이 방법들은 어육의 actomyosin toughness나 background toughness를 향상시키는 방법들이다. (중략)

• Journal of the Korean Society of Food Science and Nutrition
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• v.28 no.2
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• pp.292-298
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• 1999

Myofibril and actomyosin were prepared from red muscle and white muscle of fresh water fish and sea water fish, and their biochemical characteristics and SDS PAGE patterns of myofibril were compared. SDS PAGE analysis showed that electrophoretic patterns of myofibril were similar be tween white muscle and red muscle, while difference of 30kDa component of myofibril was detected between fresh water fish and sea water fish. When myofibril were treated with trypsin, difference in hydrolysis of heavy chain was observed between white muscle and red muscle. In activities of Ca ATPase, Mg ATPase, EDTA ATPase and ATPase activity pH curve, myofibrillar protein from fresh water fish showed higher specific activity than those from sea water fish.