• Journal of Microbiology and Biotechnology
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• 제23권12호
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• pp.1779-1784
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• 2013

Although enzyme-hydrolyzed silk fibroin has been reported to enhance cognitive function before, it has been still unknown which peptides can improve memory. Here we report that amino acid sequences of three novel peptides were identified from fibroin hydrolysate. Fibroin hydrolysate was obtained by hydrolysis with protease after partial hydrolysis with 5M $CaCl_2$. Synthesized peptides derived from these sequences improved scopolamine-induced memory impairments in mice. We confirmed this hydrolysate had effects that improved learning and memory abilities by performing the Rey-Kim test. From this hydrolysate of silk fibroin, amino acid sequences of eight peptides were identified by LC-MS/MS. Three peptides (GAGAGTGSSGFGPY, GAGAGSGAGSGAGAGSGAGAGY, and SGAGSGAGAGSGAGAGSGA) were synthesized to investigate whether they could improve memory. Passive avoidance test and Morris water maze test were performed, and all peptides showed memory-enhancing abilities on scopolamine-induced memory impairments in mice. In this study, we identified three novel peptides that could improve memory, and that silk fibroin hydrolysate was a mixture of various active peptides that could enhance memory.

• 생약학회지
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• 제33권4호통권131호
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• pp.312-318
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• 2002

Effect of the acid hydrolysate of silk fibroin on obesity was investigated in obese(057BL/KsJ-db/db) mice. After 8 weeks feeding of 1%(w/w) or 3%(w/w) fibroin hydrolysate, the extents of reduction in body weight were significantly higher than that of obese control. The weight reduction in female mice was higher than that in male mice. Plasma leptin in male mice increased up to 1.8-fold higher level than obese control by feeding hydrolysate. In case of female mice, however, it rather decreased with increased feeding concentration of hydrolysate. From the results of high glycine and serine contents of peptide fractions contained in fibroin hydrolysate, it was inferred that fibroin peptides might affect xylosyltransferase(XT) activity on chondroitin sulfate synthesis causing to change susceptibility of adipocytes to hormones such as insulin followed by the reduced leptin synthesis in female mice. The result of the higher lipolysis in hydrolysate-fed group than obese control indicated that the reduction in body weight was due to the increased lipolytic activities in male and female mice in common.

• 생약학회지
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• 제33권1호통권128호
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• pp.21-28
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• 2002

Antidiabetic effects of the acid hydrolysate of silk fibroin were investigated by oral administration to animal models for diabetes mellitus, Fibroin protein was extracted from cocoon and digested to peptides of low-molecular weight range (mainly below 3,000) and amino acids by acid hydrolysis, Feeding of the fibroin hydrolysate resulted in a significant recovering effect on reduction of body weight gain and a lowering effect on blood glucose gain in streptozotocin-induced diabetic Sprague Dawley rats (STZ rats) which were used as an insulin-dependent diabetic animal model. But the body weight and blood glucose level in C57BL/KsJ-db/db mice (db/db mice), an non-insulin-dependent diabetic animal model, were not changed significantly by the feeding, On the other hand, plasma leptin levels increased according to increased feeding amount of the hydrolysate in STZ rats and db/db mice in common, It was concluded from the results that the fibroin hydrolysate might stimulate the insulin secretion by recovering or activating pancreatic ${\beta}$ cells and result in the increased plasma leptin level. It was also deduced that the antidiabetic improvements in body weight and blood glucose gain in STZ were thought to be due to the increased insulin secretion, but in db/db mice of which the diabetic symptoms were caused by insulin resistance, the stimulated secretion of insulin was unlikely to be able to change body weight and blood glucose level significantly.

• 한국잠사곤충학회지
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• 제41권3호
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• pp.211-215
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• 1999

The pure-separation of calcium chloride-treated fibroin hydrolysates could be carried out using gel filtration chromatography. Also, the effect of its enzymatic hydrolysis was investigated in order to find out the enhancement of their functionality. The average molecular weight(Mw), solubility and free amino acid compositions of three hydrolysates samples (calcium chloride, calcium chloride-flavourzyme and calcium chloride-thermoase)were measured to compare their characteristics. The molecular weight of calcium chloride hydrolysate was about Mw 46,800 and it can be reduced to Mw 12,500 and 1,070 upon the enzymatic hydrolysis by flavourzyme and thermoase, repectively. A solubility of calcium chloride-treated samples shows about 60% while calcium chloride/enzyme-treated samples are perfectly soluble (100% solubility). The total amino acid composition of calcium chloride enzymatic hydrolysates are much higher than that of calcium chloride hydrolysate.

• International Journal of Industrial Entomology and Biomaterials
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• 제21권2호
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• pp.169-174
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• 2010

Hydrolysate silk fibroin (HSF) is a fibrous protein composed of parallel $\beta$-structures and is made from pure silk elements including 18 amino acids, with glycine, alanine, and serine comprising of over 80% of the amino acids. Numerous studies have documented a range of effects of HSF, including moisturizing, antioxidant activity, nervous system disorders, and many more. We investigated whether HSF has anti-obesity effects in vitro. The effects of HSF inhibition on lipid accumulation and acceleration of lipid degradation in 3T3-L1 cells were studied. Treatment of 3T3-L1 cells with HSF caused significant inhibition of cell viability, an increase in glycerol release, and a decreased in adipocyte differentiation. Moreover HSF stimulated downregulated of adipogenic enzyme expressions (PPAR${\gamma}$ and C/EBP${\alpha}$) and up-regulated of fatty oxidation enzyme expressions (CPT-1 and UCP-2). Based on these results, hydrolysate silk fibroin can be suggested as a potential therapeutic substance as part of a prevention or treatment strategy for obesity.

• 한국잠사학회:학술대회논문집
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• 한국잠사학회 2003년도 International Symposium of Silkworm/Insect Biotechnology and Annual Meeting of Korea Society of Sericultural Science
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• pp.53-54
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• 2003

The silk fibroin has been widely used as industrial materials such as cosmetics and food l)-2). In this study, general hydrolysate of B. mori fibroin as a biomaterial, development of functional-cometics included hydrolysate of B. mori fibroin will be discussed. (omitted)

• 한국미생물·생명공학회지
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• 제30권1호
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• pp.39-45
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• 2002

실크 피브로인의 가수분해를 통해 생산된 펩타이드 성분에 의해 murine macrophage RAW264.7 세포에 의한 nitric oxide 생성이 촉진됨을 발견하였다. 산 및 효소적 가수분해물의 가수분해도를 비교한 결과 실크 피브로인 단백질은 산 가수분해에 의해 가장 효과적으로 분해되었으며 효소적 가수분해의 경우에는 pepsin, trypsin, Alcalase의 순으로 가수분해도가 높았다. 산 가수분해물을 단독으로 macrophage에 처리하였을 때 처리농도에 따라 NO 생성촉진활성이 높아졌으나 이 활성은 가수분해물 내의 펩타이드 성분들과 오염되어 혼재하는 LPS 성분의 상호작용에 의한 것임이 확인되었다. 함유된 LPS 성분들을 한외여과에 의해 제거한 효소적 가수분해물들의 NO 생성촉진활성은 peptic hydrolysate가 가장 높았고 tryptic-, Alcalase hydrolysate 순이었다. 이러한 활성의 차이는 가수분해물 내의 고분자량 펩타이드 분포가 많을수록 활성이 높다는 관계에 기인하였으나 산 가수분해물의 경우에는 예외적으로 나타났다. 각 가수분해물의 아미노산 조성을 분석한 결과 arginine, lysine의 함량이 높을수록 활성이 높으며 alanine의 glycine에 대한 비율이 커질수록 활성이 높아졌다. 산 가수분해물의 경우에는 낮은 분자량의 펩타이드들이 많이 분포하지만 arginine 및 alanine의 함량이 높아 비교적 높은 NO 생성 촉진활성을 나타내는 것으로 확인되었다.

• 한국잠사곤충학회지
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• 제46권1호
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• pp.23-27
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• 2004

견 피브로인 가수분해물의 몇 가지 특성과 in vitro 및 in vivo에 의한 동물 인지 기능 향상효과를 알아본 결과, 다음과 같은 결과를 얻을 수 있었다. 1) 효소 가수분해 실크 피브로인 펩타이드의 분획에 있어 3가지의 분자량이 다른 분획을 제조할 수 있었다. 2) 분획 별 실크 피브로인 펩타이드의 유리 아미노산 조성은 분획간의 유의차가 나타났으며, 분획 2 및 3의 경우 활성부분을 가진 Cys, Tyr 및 Phe부분이 상당한 양을 차지하였다. 3) 대표적으로 산 및 효소 가수분해물의 핵자기공명(NMR) 법에 의한 구조적 차이는 산으로 가수분해한 저분자와 그렇치 않은 샘풀 간에는 확실한 구조적 차이에 기인한 상이한 스펙트럼을 관측할 수 있었다. 4) 분자량 별 실크 피브로인의 인지기능 향상 효과를 세포배양(in vitro)및 동물투여(in vivo)에 의해 알아본 결과, 세포배양에 의한 활성 효과는 분자량에 따라 다소 차이가 나타났으며, 그 중 분자량 500미만의 샘플군(LF)이 대조인 유발군에 비해 23.5%의 세포보호 효과가 있었다. 또한 동물(in vivo)에 의한 인지기능 향상 효과에 있어서는 보다 확실한 차이가 나타났는데, 그 중 분자량 500-1000정도의 분자량 범위의 분획물질을 10 mg/kg을 투여하였을 경우, 대조군(scopolamine)에 비하여 최고 50%까지 기억회복 효과를 나타내었다.

• International Journal of Industrial Entomology and Biomaterials
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• 제27권2호
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• pp.228-236
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• 2013

Breast cancer is one of the most common cancers among women worldwide. Recently anticancer agents have been developed using natural substances. To evaluate the anticancer effect of hydrolysates of silk fibroin (HSF), we investigated the effect of HSF on cell viability and apoptosis of a breast cancer cell line, MCF-7, induced through the mitochondrial pathway. The result showed that HSF decreased cell viability in MCF-7 cells in a dose- and time-dependent manner, resulting in an increase in the sub-G1 phase cell population. HSF increased the level of the pro-apoptotic Bax protein and decreased the levels of the anti-apoptotic Bcl-2 protein. In addition, HSF induced apoptosis in MCF-7 cells through a mitochondria-dependent pathway by increasing levels of cytochtome c, and cleavage of PARP. Taken together, these findings suggest that HSF inhibits the proliferation of MCF-7 breast cancer cells through a mitochondria and caspase dependent apoptotic pathway.

• International Journal of Industrial Entomology and Biomaterials
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• 제2권1호
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• pp.7-13
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• 2001

Enzymatic hydrolysis of different forms of silk fibroin (soluble, gel and insoluble forms) by industrial and commercial enzyme preparations to obtain aqueous and powdered silk fibroin in relatively mild conditions was investigated. A mono-enzymatic hydrolysate systems were tested for hydrolysis of water-soluble form of fibroin as most productive form of protein substrate. Insoluble forms of substrate usually were hydrolyzed less effective. In some cases from soluble fibroin substrate gel was formed during hydrolysis process. This hindered intermixing and decreased rates of hydrolysis. Insoluble sediments were formed in enzymatic hydrolysates in other cases. These sediments and also sediment after chemical hydrolysis were purified and tested on amino acids content for comparison. Sediments formation in these conditions are considered as pure tyrosine isolation method. Obtained hydrolysates were characterized by gel-chromatography analysis and other standard biochemical methods. Possibility of application of enzymatic hydrolysis for preparation of silk fibroin hydrolysates is discussed.