본 연구에서는 가교 분자를 사용하여 0.7 kPa에서 17.7 kPa까지 다양한 강도를 갖는 콜라겐 겔을 성공적으로 제조하였다. 가교된 콜라겐 겔에 다공성 기공을 도입하고 진피세포를 내부에 담지하여, 겔 강도에 따른 세포 성장 및 거동을 확인하였다. 상대적으로 강도가 높은 겔에서 진피세포의 프로콜라겐 생합성이 47 ng에서 32 ng까지 감소하는 것을 확인하였다. 이렇게 제조된 인공피부 진피에 아데노신을 처리하였을 때, 특정 강도를 갖는 콜라겐 겔에서 프로콜라겐 생합성이 감소하는 것을 확인하였다. 반면에 기능성 펩타이드를 처리하였을 때 는 프로콜라겐 생합성이 콜라겐 겔의 강도에 크게 영향을 받지 않는 것을 확인할 수 있었다. 이러한 결과는 강도가 제어된 인공피부 제조 및 응용, 나아가 다양한 조직공학 분야의 기반 기술로 활용 가능하리라 기대된다.

본 연구에서는 단백질 함량이 높은 들깨박을 기능성 식품소재로서의 활용가능성을 확인하기 위하여 단백질분해효소 및 한외여과를 이용하여 가수분해물과 펩타이드 분획을 제조하고 이들의 항산화 활성을 측정하였다. 먼저 들깨박단백질의 가수분해물 생산을 위한 최적 효소를 선정하기 위해 단백질분해효소 7종을 이용하여 효소 반응 후 가수분해도를 측정한 결과, flavourzyme이 가장 높은 가수분해율을 나타내었다. Flavourzyme에 의한 들깨박단백질 가수분해물을 얻기 위한 최적 조건은 pH 7.0, 50℃, 효소농도 10 unit, 가수분해시간은 4시간으로 결정되었다. 들깨박단백질 가수분해물을 한외여과 후 얻은 각 분획의 수율은 1 kDa 이하가 45.65%로 유의적으로 가장 높았으며, 그 다음으로5-10 kDa(16.45%), 10 kDa 이상(16.37%), 1-3 kDa(10.86%), 3-5 kDa(10.67%) 순으로 높았다. DPPH 라디칼 소거능은 효소가수분해물이, 환원력은 3-5 kDa 분획물이, superoxide dismutase 유사활성은 1 kDa 이하의 분획물이 가장 높은 활성을 나타내었다. 따라서 들깨박단백질로부터 생산된 가수분해물 및 펩타이드 분획은 각기 다른 항산화 활성 특성을 보여 기능성 식품 소재의 목적에 맞게 선택하여 활용할 수 있을 것으로 판단된다. 또한 향후 식품학적 기능성 평가가 이루어진다면 식품산업에서 다양한 식품재료로의 활용성이 확대될 수 있을 것으로 판단된다.

저활용 단백질로부터 칼슘 결합물질을 분리하기 위해 돼지 육골분과 진주담치 단백질을 단백질 분해 효소인 alcalase를 이용하여 가수분해물을 제조하였고, 체내 흡수가 용이한 3 kDa 이하로 한외여과 하였다. 돼지 육골분 가수분해물은 Mono Q 컬럼을 통해 분리하였고, 진주담치가수분해물의 경우 Q-Sepharose로 분리 하여 각각 2개, 3개의 peptide fraction을 얻어 각 fraction의 칼슘 결합력을 측정하였다. 그 결과 MBM F2와 Mussel F3에서 가장 높은 칼슘결합력을 나타내었고, 따라서 본 연구 결과로 얻어진 가수분해물들은 칼슘 보충 소재로 활용될 수 있다고 판단된다.

Sorghum seed is traditionally used as secondary food sources in addition to rice in Korea. While the hypoglycemia regulating phytochemicals have been found in sorghum seed, peptides related with hypoglycemia never been studied before. To obtain the peptide characteristics and the specifically high-expressed peptides in hypoglycemic sorghum seed, peptide profiles of seven hypoglycemic and five nonhypoglycemic sorghum lines bred in RDA were determined using surface-enhanced laser desorption/ionization time-offlight mass spectrometry (SELDI-TOF MS). The twelve sorghum lines exhibited 104 peptides on CM10 protein chip array (weak cation exchange) and 95 peptides on Q10 (weak cation exchange) in the molecular mass range from 2,000 to 20,000 Da. Heat map via supervised hierarchical clustering of the significantly different peptides (p < 0.01) in peak intensity among the 12 lines effectively revealed the specifically upregulated peptides in each line and distinguished between 7 hypoglycemic and 5 non-hypoglycemic lines. Through the comparison with hypoglycemic and non-hypoglycemic lines, 10 peptides including 2231.6, 2845.4, 2907.9, 3063.5, 3132.6, 3520.8, 4078.8, 5066.2, 5296.5, 5375.5 Da were specifically high-expressed in hypoglycemic lines at p < 0.00001. This study characterized seed peptides of 12 sorghums and found ten peptides highly expressed for hypoglycemic sorghum lines, which could be used as peptide biomarkers for identification of hypoglycemic sorghum.

As byproducts of chicken slaughtering, chicken feathers are produced and mostly discarded without proper treatment, which results in serious environment pollution. Therefore, the appropriate treatment and utilization of chicken feathers are needed. In particular, chicken feathers can be used as protein sources for the preparation of protein hydrolysates, considering that chicken feathers have a large amount of proteins. In this study, chicken feather protein hydrolysates were prepared and their iron-binding peptides were isolated. Chicken feather protein was extracted from feathers of slaughtered chicken, and its hydrolysates were prepared via hydrolysis with Flavourzyme for 8 h. Then the chicken feather protein hydrolysates were ultra-filtered to obtain small peptide fractions and fractionated using Q-Sepharose and Sephadex G-15 columns to isolate their iron-binding peptides. Two major fractions were produced from each of the Q-Sepharose ion exchange chromatography and the Sephadex G-15 gel filtration hromatography. Among the fractions, the peptide fraction with a high iron-binding activity level, F12, was isolated. These results suggest that chicken feather protein hydrolysates can be used as iron supplements.

The antimicrobial peptide possesses defence system to virus, fungi and bacteria. To study antibiotic in plant, antimicrobial peptides were obtained by PCR analysis by primers designed from antimicrobial peptides (Gene bank accession no. NM-004345), cloned in pET28 expression vector and the vector transformed into E. coli. And this gene was inserted into Ti-plasmid VB2 vector, which contained the pGD1 promoter. The expression construction was transformed into Agrobacterium EHA105 and then plant tissues of rice (Oryza sativa). Seeds from transgenic plants (T0) were germinated on selective media containing spectinomycin 50 mg/L. Selected plants and wild type were analyzed by PCR and RT-PCR with pGD1 promoter region and transgene specific primer set. All transgenic plants showed expression pattern of similar levels. We showed that the chromobody is effective in binding GFPand antimicrobial peptide gene in tobacco leaf. Most interestingly, this can be applied to interfere with the function of GFP fusion protein and to mislocalize (trap) GFP fusions to the plant cytoplasm in order to alter the phenotype mediated by the targeted proteins. Bacterial blight disease was enhanced resistance in transgenic lines. These results showed that antibiotic peptides might show a broad-spectrum antimicrobial activity.

To prepare calcium-binding peptides as calcium supplement, barley proteins were hydrolyzed using Flavourzyme for 18 h and the hydrolysates were ultra-filtered under 3 kDa as a molecular weight. The resultant filtered peptides were fractionated using ion exchange and normal-phase high performance liquid chromatography. Then each fraction that was obtained was determined for its calcium-binding activity to isolate the calcium-binding peptides. As a result, the highest calcium-binding peptide fraction was obtained, and the results suggest that barley protein hydrolysates can be used as a calcium supplement.

The objectives of present study were to characterize the peptides which were isolated from Korean fermented soybean paste, chungkukjang, and to determine their antioxidant activities. Four fractions were collected from the methanol extract of chungkukjang by using a recycling preparative HPLC. Among fractions, Fr-2 was identified to be highly potent free radical scavenging activity in the assay of 1,1-diphenyl-2-picryl-hydrazyl (DPPH) and nitroblue tetrazolium(NBT)-reduction inhibition. Base on antioxidant effects, fraction Fr-2 was employed for the refraction with a prep-column and separated into five fractions of which two fractions were identified to have higher antioxidant activity. To confirm the amino acid constituents of antioxidant fractions Fr-2-2 and Fr-2-3 were analyzed, and eight kinds of amino acids such as aspartic acid, threonine, serine, glutamic acid, glycine, lysine, histidine, and arginine were identified as the constituent amino acids. Antioxidant activities of the separated peptides were further assessed cell viability with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl terazolium bromide (MTT), and fluorescence-activated cell sorting (FACS) analysis of H4IIE cells treated with hydrogen peroxide (H2O2). Chungkukjang peptides have shown their ability to protect H4IIE rat hepatoma cells against H2O2- induced oxidative stress by concentration and time-dependent manner. Therefore, These results indicated that fermented soybean paste chungkukjang will be promoted the antioxidant and radical scavenging activities, and beneficial for health. The antioxidant peptide fractions Fr-2-2 and Fr-2-3 were denominated as P-NICS-1 and P-NICS-2, respectively. However, further studies were required to clarify their amino acid sequences and molecular properties, and physiological significances.

Post-translational covalent modifications by small molecules or peptides remodel target proteins. One such modification, made by ubiquitin or small ubiquitin-related modifier (SUMO), is a rapidly expanding field in cell signaling pathways. Ubiquitin attachment controls the turnover and degradation of target proteins while SUMO conjugation regulates their activity and function. Recent studies report many examples of cross-talk between ubiquitin and SUMO pathways, indicating that the boundary is no longer clear. Here, we review recent progress concerning how ubiquitin and SUMO participate in new regulatory roles in plant cell, and how ubiquitination and sumoylation control plant growth and development.