• BMB Reports
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• 제45권2호
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• pp.114-119
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• 2012

Salsolinol (1-methyl-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline) is a compound derived from dopamine metabolism and is capable of causing dopaminergic neurodegeneration. Oxidative modification of neurofilament proteins has been implicated in the pathogenesis of neurodegenerative disorders. In this study, oxidative modification of neurofilament-L (NF-L) by salsolinol and the inhibitory effects of histidyl dipeptides on NF-L modification were investigated. When NF-L was incubated with 0.5 mM salsolinol, the aggregation of protein was increased in a time-dependent manner. We also found that the generation of hydroxyl radicals (${\bullet}OH$) was linear with respect to the concentrations of salsolinol as a function of incubation time. NF-L exposure to salsolinol produced losses of glutamate, lysine and proline residues. These results suggest that the aggregation of NF-L by salsolinol may be due to oxidative damage resulting from free radicals. Carnosine, histidyl dipeptide, is involved in many cellular defense processes, including free radical detoxification. Carnosine, and anserine were shown to significantly prevent salsolinol-mediated NF-L aggregation. Both compounds also inhibited the generation of ${\bullet}OH$ induced by salsolinol. The results indicated that carnosine and related compounds may prevent salsolinol-mediated NF-L modification via free radical scavenging.

• Journal of Applied Biological Chemistry
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• 제66권
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• pp.171-178
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• 2023

Morus alba, a popular medicinal plant belonging to the family Moraceae, has long been used commonly in traditional medicine and has various physiological activities, including antidiabetic, anti-microbial, diuretic, anti-oxidant, and anti-cancer activities. Morusinol was isolated from the root bark of M. alba; however, its biological effects have not yet been reported. Therefore, we examined the inhibitory effects of morusinol on human platelet aggregation, Ca²⁺ mobilization, and αIIb/β₃ activity. Our data showed that collagen-induced human platelet aggregation was inhibited by morusinol without cytotoxicity. In this study, we examined whether morusinol inhibits platelet aggregation through the regulation of integrin αIIb/β₃ and its associated signaling molecules. We observed that morusinol inhibited αIIb/β₃ activation by regulating vasodilator-stimulated phosphoprotein, phosphatidylinositol-3 kinase, Akt (protein kinase B), and glycogen synthase kinase-3α/β. These results show that morusinol inhibited fibronectin adhesion, fibrinogen binding, and clot retraction. Taken together, morusinol shows strong antiplatelet and anti-clot retraction effects and is a potential therapeutic drug candidate to prevent platelet-related thrombosis and cardiovascular disease.

• Mass Spectrometry Letters
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• 제15권1호
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• pp.62-68
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• 2024

The Suspension Trapping (S-Trap) method has been a prominent sample preparation technique since its introduction in 2014. Its capacity to induce protein aggregation using organic solvents has significantly improved protein purification and facilitated peptide identification. However, its full potential for automation has been limited by the lack of a suitable liquid handling system until recently. In this study, we aimed to enhance the automation of S-Trap sample preparation by optimizing the S-Trap digestion process, incorporating triethylammonium bicarbonate (TEAB) and CaCl₂. The utilization of TEAB buffer conditions in this innovative process led to a noteworthy 12% improvement in protein identification. Additionally, through careful observation of various incubation conditions, we streamlined the entire sample preparation workflow into a concise 4 hours timeline, covering reduction, alkylation, and trypsin incubation stages. This refined and expedited automated S-Trap digestion process not only showcased exceptional time efficiency but also improved trypsin digestion, resulting in increased protein identification.

• 한국축산식품학회지
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• 제39권2호
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• pp.296-308
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• 2019

Although the yellow mealworm (Tenebrio molitor L.) is a promising alternative protein source, the effects of processing conditions on functional properties are unclear. In this study, a protein extract of yellow mealworm larvae (PEYM) was subjected to different heat temperature ($55^{\circ}C$, $75^{\circ}C$, and $95^{\circ}C$) with different time (20, 40, and 60 min) to evaluate the functional properties and protein oxidation. Different heat temperature treatment significantly affected the exposure of surface hydrophobicity of the proteins and protein molecule aggregation, which reached maximum levels at $95^{\circ}C$ for 60 min. Protein oxidation was inversely proportional to the temperature. Both the highest carbonyl value (1.49 nmol/mg protein) and lowest thiol value (22.94 nmol/mg protein) were observed at $95^{\circ}C$ for 60 min. The heating time-temperature interaction affected several functional properties, including solubility, emulsifying potential, and gel strength (GS). Solubility decreased near the isoelectric point (pH 5 to 6). As the temperature and heating time increased, emulsifying properties decreased and GS increased. The oil absorption capacity and foaming properties decreased and the water absorption capacity increased. These results confirmed that PEYM is a suitable source of proteins for processing and applications in the food industry.

• 생명과학회지
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• 제17권2호통권82호
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• pp.211-217
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• 2007

이 연구의 목적은 대장균 분자 샤페론 GroEL의 시험관 내 단백질 접힘에 있어서 반응온도의 영향과 보조샤페론의 필요 여부를 자발적 재접힘이 가능한 온도와 그렇지 않은 온도조건에서 조사하는 것이다. 여러 조건하에서 GroEL에 의한 두 가지 기질 단백질의 재접힘을 반응속도론적으로 조사하기 위하여 GroEL에 의한 단백질 침전생성억제와 변성된 단백질의 재접힘을 광범위하게 조사하였다. 자발적 재접힘이 가능하지 않은 $37^{\circ}C$에서는 ATP와 완전한 GroEL 시스템이 변성된 폴리펩티드의 재접힘을 위하여 필요하다는 것을 확인하였다. 하지만, 자발적 재접힘이 가능한 낮은 온도에서는 자발적 재접힘과 샤페론 의존적 단백질 재접힘이 서로 경쟁하는 것을 알 수 있었다. 따라서 GroEL은 변성된 폴리펩티드의 자발적 접힘 경로를 더 효율적인 단백질 재접힘 경로인 샤페론 의존적 단백질 재접힘 경로로 유도하는 것으로 보인다.

• BMB Reports
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• 제36권5호
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• pp.488-492
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• 2003

Neurofilament-L (NF-L) is a major element of neuronal cytoskeletons and known to be important for neuronal survival in vivo. Since oxidative stress might play a critical role in the pathogenesis of neurodegenerative diseases, we investigated the role of copper and peroxide in the modification of NF-L. When disassembled NF-L was incubated with copper ion and hydrogen peroxide, then the aggregation of protein was proportional to copper and hydrogen peroxide concentrations. Dityrosine crosslink formation was obtained in copper-mediated NF-L aggregates. The copper-mediated modification of NF-L was significantly inhibited by thiol antioxidants, N-acetylcysteine, glutathione, and thiourea. A thioflavin-T binding assay was performed to determine whether the copper/$H_2O_2$ system-induced in vitro aggregation of NF-L displays amyloid-like characteristics. The aggregate of NF-L displayed thioflavin T reactivity, which was reminiscent of amyloid. This study suggests that copper-mediated NF-L modification might be closely related to oxidative reactions which may play a critical role in neurodegenerative diseases.

• BMB Reports
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• 제37권3호
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• pp.325-329
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• 2004

Oxidation of catecholamines may contribute to the pathogenesis of Parkinson's disease (PD). The effect of the oxidized products of catecholamines on the modification of Cu,Zn-superoxide dismutase (SOD) was investigated. When Cu,Zn-SOD was incubated with the oxidized 3,4-dihydroxyphenylalanine (DOPA) or dopamine, the protein was induced to be aggregated. The deoxyribose assay showed that hydroxyl radicals were generated during the oxidation of catecholamines in the presence of copper ion. Radical scavengers, azide, N-acetylcysteine, and catalase inhibited the oxidized catecholamine-mediated Cu,Zn-SOD aggregation. Therefore, the results indicate that free radicals may play a role in the aggregation of Cu,Zn-SOD. When Cu,Zn-SOD that had been exposed to catecholamines was subsequently analyzed by an amino acid analysis, the glycine and histidine residues were particularly sensitive. These results suggest that the modification of Cu,Zn-SOD by oxidized catecholamines might induce the perturbation of cellular antioxidant systems and led to a deleterious cell condition.

• 한국생물물리학회:학술대회논문집
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• 한국생물물리학회 2003년도 정기총회 및 학술발표회
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• pp.57-57
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• 2003

In growing number of diseases it has been shown that aggregation of specific proteins has an important role in pathogenesis of the disorder. This has been demonstrated in structural details with the liver cirrhosis of ${\alpha}$$_1$-antitrypsin deficiency, and it is now believed that similar protein aggregation underlies many neurodegenerative disorders such as autosomal dominant Parkinson disease, prion diseases, Alzheimer disease, and Huntington disease. ${\alpha}$$_1$-Antieypsin, a member of serine pretense inhibitor (serpin) family, functions as an inhibitor of neutrophil elastase.

• Mycobiology
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• 제43권3호
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• pp.272-279
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• 2015

To screen molecular chaperones similar to small heat shock proteins (sHsps), but without ${\alpha}$-crystalline domain, heat-stable proteins from Schizosaccharomyces pombe were analyzed by 2-dimensional electrophoresis and matrix assisted laser desorption/ionization time-of-flight mass spectrometry. Sixteen proteins were identified, and four recombinant proteins, including cofilin, NTF2, pyridoxin biosynthesis protein (Snz1) and Wos2 that has an ${\alpha}$-crystalline domain, were purified. Among these proteins, only Snz1 showed the anti-aggregation activity against thermal denaturation of citrate synthase. However, pre-heating of NTF2 and Wos2 at $70^{\circ}C$ for 30 min, efficiently prevented thermal aggregation of citrate synthase. These results indicate that Snz1 and NTF2 possess molecular chaperone activity similar to sHsps, even though there is no ${\alpha}$-crystalline domain in their sequences.

• 한국식품조리과학회지
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• 제20권3호
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• pp.256-264
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• 2004

The effects of irradiation on the functional and structural characteristics of soy protein isolates were studied. Soymilk was irradiated at 1, 5, and l0kGy, after which soy protein isolates were prepared. The functional properties of soy protein isolates were examined including solubility, emulsion capacity and stability, foam capacity and stability, structural properties as represented by SDS-PAGE pattern, and secondary and tertiary structures. The solubility and emulsion capacity were increased by radiation treatment at 1kGy however the values were adversely affected again as dosage was increased above 5kGy. As irradiation dosage increased, an increase of foaming capacity at 1kGy and a decreasing turnover afterwards were also noted in foaming capacity, although the differences were not statistically significant. The SDS-PAGE pattern showed fragmentation and aggregation of protein molecules as affected by irradiation in proportion to the dosage increase. The results of CD and fluorescence spectroscopy revealed increased aperiodic structure contents with the dosage increase. It was assumed that irradiation dosagefrom 5 to l0kGy could initiate minimal denaturation of protein in various foods compared to general heat treatment.