• Bulletin of the Korean Chemical Society
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• 제23권5호
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• pp.647-654
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• 2002

The synthesis and characterization of third- and fifth-generation poly(propylene imine) dendrimers terminated with imidazole moieties is reported. Functionalization was achieved using simple peptide coupling reagents. These materials were characte rized by MALDI-MS, NMR, and titration. The use of these endgroup-functionalized dendrimers as catalysts for the hydrolysis of 2,4-dinitrophenyl acetate is described. Molecular simulations provide a basis for interpreting the catalytic data.

• Mass Spectrometry Letters
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• 제9권2호
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• pp.46-50
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• 2018

The effects of temperature and acetonitrile (ACN) concentration on microwave-assisted weak-acid hydrolysis of proteins were investigated. Myoglobin was hydrolyzed for 1 h using 2% formic acid and a microwave with different concentrations of ACN (0, 5, and 10%) at various temperatures (50, 60, 70, 80, 90, and $100^{\circ}C$). The numbers of peptides identified with each concentration of ACN were the same for each temperature. The greatest number of peptides (18 total) was obtained with hydrolysis at $100^{\circ}C$, and 6 of these were a result of additional removal of aspartic acid at the C-terminus. Hydrolysis at $80^{\circ}C$ resulted in 13 peptides, of which only 1 was generated by the additional removal of aspartic acid, and 12 were observed with hydrolysis at $100^{\circ}C$. Our results demonstrate that microwave-assisted weak-acid hydrolysis of proteins can be performed successfully at $80^{\circ}C$, which could be beneficial for limiting side reactions and generating larger peptide sequences.

• 한국축산식품학회지
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• 제29권5호
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• pp.633-639
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• 2009

본 연구는 유단백질에 단백질 분해효소를 처리하여 가수분해 후 저분자 peptide를 ABTS법을 이용하여 항산화 활성을 측정하여 유단백질 유래 저분자 peptide의 항산화력을 측정하고자 하였다. Chymotrypsin 처리한 유청단백질의 가수분해도가 가장 높았으며, 유청단백질의 락트알부민 및 락토글로브린이 분해되어 분자량 20 kDa 이하의 저분자 단백질이 생성된 것을 전기영동을 통하여 확인하였다. 유단백질의 농도에 따른 항산화 활성을 측정한 결과, 카제인의 항산화 활성이 유청단백질보다 높게 나타났다. 유단백질을 효소에 의하여 가수분해 시 항산화 활성이 증가하였으며, 카제인 가수분해물이 유청단백질 가수분해물과 비교하여 항산화 활성이 더 높았으나, 가수분해도와 항산화 활성도의 관계는 일치하지 않았다. Trypsin에 의한 카제인 가수분해 물의 항산화 활성이 80.7%로 가장 높았다. 본 연구에서는 chymotrypsin과 trypsin에 의한 분자량 3 kDa의 카제인 분획물의 항산화 활성이 가장 우수 하였으며, 유청단백질을 trypsin으로 분해하였을 때 항산화 활성이 증가하였다.

• Applied Biological Chemistry
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• 제46권2호
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• pp.130-133
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• 2003

Hemoglobin(Hgb)의 가수분해물로부터 heme-iron을 분리하는데 영향을 미치는 Hgb의 농도, 가수분해도(DH, degree of hydrolysis), 투석용액의 pH, 투석막의 pore size에 대하여 조사하였다. 가수분해에 사용된 Hgb의 농도가 높아짐에 따라 heme-iron의 회수율은 증가하였으나, peptide의 제거율과 HP ratio(총 peptide 중 heme-iron이 차지하는 비율)는 Hgb의 농도에 따른 큰 차이를 볼 수 없었다. Hgb의 가수분해도가 8%, 16%, 24%로 증가함에 따라 투석에 의한 peptide의 제거가 용이하게 이루어져 HP ratio가 13.7%, 20.7%, 31%로 증가하였다. 투석용액에 $KH_2PO_4$를 25 mM이 되도록 첨가할 때는 HP ratio가 25.7%이었으나,50 mM이상의 농도에서는 30.0-32.5%로 증가하였다. 투석용액의 pH 높을수록 heme-iron의 용해도가 증가하여 투석막을 통한 heme-iron의 세출이 많아졌다. Peptide의 제거율은 투석막이 2kDa에서 5kDa로 커질 때 74.5%에서 87.5%의 큰 폭으로 증가하였으며, heme-iron의 회수율은 투석막의 크기에 따라 감소하여 2kDa에서는 86.5%, 15kDa에서는 79.6%, 25kDa에서 63.1%로 급감하였다. 투석법에 의해 분리, 건조된 heme-iron제품의 heme-iron과 peptide의 함량은 각각 21.7%와 77.0%이었으며, HP ratio는 28.2%, 수율은 6,5%이었다.

• Journal of Microbiology and Biotechnology
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• 제22권1호
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• pp.84-91
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• 2012

Two staphylococcal lipases were obtained from Staphylococcus epidermidis S2 and Staphylococcus aureus S11 isolated from sebaceous areas on the skin of the human face. The molecular mass of both enzymes was estimated to be 45 kDa by SDS-PAGE. S2 lipase displayed its highest activity in the hydrolysis of olive oil at $32^{\circ}C$ and pH 8, whereas S11 lipase showed optimal activity at $31^{\circ}C$ and pH 8.5. The S2 lipase showed the property of cold-adaptation, with activation energy of 6.52 kcal/mol. In contrast, S11 lipase's activation energy, at 21 kcal/mol, was more characteristic of mesophilic lipases. S2 lipase was stable up to $45^{\circ}C$ and within the pH range from 5 to 9, whereas S11 lipase was stable up to $50^{\circ}C$ and from pH 6 to 10. Both enzymes had high activity against tributyrin, waste soybean oil, and fish oil. Sequence analysis of the S2 lipase gene showed an open reading frame of 2,067 bp encoding a signal peptide (35 aa), a pro-peptide (267 aa), and a mature enzyme (386 aa); the S11 lipase gene, at 2,076 bp, also encoded a signal peptide (37 aa), pro-peptide (255 aa), and mature enzyme (399 aa). The two enzymes maintained amino acid sequence identity of 98-99% with other similar staphylococcal lipases. Their microbial origins and biochemical properties may make these staphylococcal lipases isolated from facial sebaceous skin suitable for use as catalysts in the cosmetic, medicinal, food, or detergent industries.

• KSBB Journal
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• 제13권1호
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• pp.114-118
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• 1998

실크의 피브로인 단백짐의 가수분해에 의한 실크 펠타이드의 제조를 위하여 설크의 가용화 조건이 분자량 분포에 미치는 영 향을 고찰하였다 염 화칼숨, ethylenediamine 및 황산에 의해 가용화된 실크의 평균 분자량은 각각 41600, 3308과 1268 dalton 으로서 염화칼숨을 제외한 나머지 두 가용화 방법에서 평균 분 자량이 수천 dalton인 실크 용액을 얻을 수 있었으며 분산계수 는 3-4의 범위뜰 보였다. 가용화 및 분말화한 후 6시간 동안 단백질 분해효소 처리에 의하여 600-1200 dalton의 중량평균 분 자량을 갖는 살크 접타이드틀 얻을 수 있었다. 24시간 염산에 의한 산분해 처리에 의해 얻은 실크 웹타이드의 평균 분자량은 145 dalton으로 80%의 높은 유리 아미노산 함량을 나타내었다. 여러가지 가용화 방법 및 가수분해 방법 중 낮은 농도의 황산용 액으로 우선 실크를 가용화한 후 중화 및 효소처리에 의해 웹타 이드로 가수분해하는 방법이 과도한 아미노산의 유리를 억제하 면서 분자량의 조절도 용이할 것으로 판단되었다.

• Asian-Australasian Journal of Animal Sciences
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• 제16권10호
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• pp.1460-1468
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• 2003

An experiment was conducted to quantify the flow of soluble non-ammonia nitrogen (SNAN) in the liquid phase of ruminal (RD) and omasal digesta (OD), and to investigate diurnal pattern in SNAN flow in OD. Five ruminally cannulated Finnish-Ayrshire dairy cows in a $5{\times}5$ Latin square design consumed a basal diet of grass silage and barley grain, and that supplemented with four protein feeds (kg/d DM basis) as follows: skimmed milk powder (2.1), wet distiller' solubles (3.0), untreated rapeseed meal (2.1) and treated rapeseed meal (2.1). Ruminal digesta was sampled using a vacuum pump, whereas OD was collected using an omasal sampling system at 1.0 h interval during a 12 h feeding cycle. Both RD and OD were acidified, centrifuged to remove microbes and precipitated with trichloroacetic acid followed by centrifugation. The SNAN fractions (free amino acid (AA), peptide and soluble protein) in RD and OD were assessed using ninhydrin assay. Free AA, peptide and soluble protein averaged 60.0, 89.4 and 2.1 g/d, respectively, for RD, and 81.8, 121.5 and 2.5 g/d, respectively, for OD. Although free AA flow was relatively high, mean peptide flow was quantitatively the most important fraction of SNAN, indicating that degradation of peptide to AA rather than hydrolysis of soluble protein to peptide or deamination may be the most limiting step in rumen proteolysis. Diurnal pattern in flow of peptide including free AA in OD during a 12 h feeding cycle peaked 1 h post-feeding, decreased by 3 h post-feeding and was relatively constant thereafter. Protein supplementation showed higher flow of peptide including free AA immediately after feeding compared with no supplemented diet. There were no differences among protein supplements in diurnal pattern in flow of peptide including free AA in OD.

• Journal of Microbiology and Biotechnology
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• 제31권1호
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• pp.33-42
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• 2021

Due to the potential of antioxidants to scavenge free radicals in human body, it is important to be able to prepare antioxidant peptides that meet the industrial requirements for cosmetics and food. Here, we determined in vivo/in vitro activities of antioxidant peptide from P. fucata (PFAOP) prepared by bio-fermentation method. The antioxidant property test results showed the DPPH, hydroxyl, superoxide radical-scavenging, and cellular antioxidant activity. EC50 values of PFAOPs were 0.018 ± 0.005, 0.126 ± 0.008, 0.168 ± 0.005, and 0.105 ± 0.005 mg/ml, respectively, exhibiting higher antioxidant activities than glutathione (p < 0.05). Moreover, anti-proliferation and cytotoxicity activity results illustrated PFAOP has a potent anti-proliferative activity against HepG2, Caco-2, and MCF-7 carcinoma cells with no cytotoxicity. Moreover, the protocols we developed in this work demonstrated several excellent advantages in PFAOP preparation compared to enzymatic hydrolysis or chemical synthesis methods and provide a theoretical foundation for higher-value application of marine-derived functional peptides.

• Journal of Microbiology and Biotechnology
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• 제9권4호
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• pp.509-513
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• 1999

The molecular size reduction and the formation of bitterness during a tryptic hydrolysis of soybean 11S glycinin were determined by using quantitative analysis and organoleptic evaluation. The 11S glycinin of 90% purity was prepared by cryoprecipitation and Con A Sepharose 4B affinity chromatography, and hydrolyzed with trypsin in a pH-stat reactor for 4 h. Bitterness was formed within 1 h of hydrolysis, and then slowly increased up to $3.5\times10^{-5}$ M quinine-HCl equivalent. The extent of hydrolysis (DH) was 7% at 1 h and increased up to 12% by the end of the reaction. The -amino nitrogen content increased from an initial 0.7 mM to 7 mM at the end of the period. The SDS-PAGE analysis showed that the acidic subunit of 11S glycinin was mostly hydrolyzed. The GP-HPLC analysis indicated that the bitterness was mainly contributed by the peptide fractions of molecular weights of 360-2,100 Da.

• Fisheries and Aquatic Sciences
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• 제25권7호
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• pp.357-379
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• 2022

Increased fisheries products have raised by-products that are discarded due to low economic value. In addition, marine by-products are still rich in protein and nutritional value that have biological activities and give benefits to human health. Meanwhile, there is raised pressure for sustainability practices in marine industries to reduce waste and minimize the detrimental effect on the environment. Thus, valorization by-products through bioactive peptide mining are crucial. This review focus on various ways to obtain bioactive peptides from marine by-products through protein hydrolysis, for instance chemical hydrolysis (acid and based), biochemical hydrolysis (autolysis and enzymatic hydrolysis), microbial fermentation, and subcritical water hydrolysis. Nevertheless, these processes have benefits and drawbacks which need to be considered. This review also addresses various biological activities that are favorable in pharmaceutical industries, including antioxidant, antihypertensive, anticancer, anti-obesity, and other beneficial bioactivities. In addition, some potential marine resources of Indonesia for the marine biopeptide from their by-product or undesired marine commodities would be addressed as well.