• BMB Reports
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• 제37권4호
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• pp.466-473
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• 2004

A new acid deoxyribonuclease (DNase) was purified from the cultured mycelia of Cordyceps sinensis, and designated CSDNase. CSDNase was purified by $(NH_4)_2SO_4$ precipitation, Sephacryl S-100 HR gel filtration, weak anion-exchange HPLC, and gel filtration HPLC. The protein was single-chained, with an apparent molecular mass of ca. 34 kDa, as revealed by SDS-PAGE, and an isoelectric point of 7.05, as estimated by isoelectric focusing. CSDNase acted on both double-stranded (ds) and single- stranded (ss) DNA, but preferentially on dsDNA. The optimum pH of CSDNase was pH 5.5 and its optimum temperature 55. The activity of CSDNase was not dependent on divalent cations, but its enzymic activity was inhibited by high concentration of the cation: $MgCl_2$ above 150 mM, $MnCl_2$ above 200 mM, $ZnCl_2$ above 150 mM, $CaCl_2$ above 200 mM, NaCl above 300 mM, and KCl above 300 mM. CSDNase was found to hydrolyze DNA, and to generate 3-phosphate and 5-OH termini. These results indicate that the nucleolytic properties of CSDNase are essentially the same as those of other well-characterized acid DNases, and that CSDNase is a member of the acid DNase family. To our knowledge, this is the first report of an acid DNase in a fungus.

• Applied Biological Chemistry
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• 제22권1호
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• pp.1-9
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• 1979

대두(大豆)의 ${\gamma}-conglycinin$을 정제(精製)하고 그의 물리일(物理一) 화학적(化學的) 성질(性質)을 연구(硏究)하여 다음의 결과(結果)를 얻었다. Gamma-conglycinin은 대두(大豆)의 pH 4.5, 0.2M Nacl 추출액을 Sephadex G-150으로 분리하여 얻은 7S globulin을 DEAE-Sephadex A-50으로 column chromatography하여 정제(精製)하였다. 정제된 ${\gamma}-conglycinin$은 면역전기영동(免疫電氣泳動), polyacrylamide gel 전기영동(電氣泳動)과 gel isoelectric focusing 상으로 순수(純粹)하였다. 등전점(等電點)은 pH 5.4이었으며 질소(窒素) 16.21%, mannose 4.18, glucosamine 1.21%의 함량(含量)이었다. 아미노산 조성(組成)은 일반적(一般的)으로 lysine, dicarboxylic acid와 암모니아태(態) 질소(窒素)의 함량(含量)이 높았고 함황(含黃)아미노산과 tryptophane의 함량(含量)은 낮은 편이었다. Subunit의 등전점(等電點)은 pH $4.5{\sim}5.5$에 분희(分希)하였는데 그중 pH $4.6{\sim}5.0$에 위치(位置)한 것은 분자량(分子量) 38,000의 당(糖) peptide이었으며 pH $5.0{\sim}5.5$의 것은 분자량(分子量) 32,000의 단순(單純) peptide이었다.

• Journal of the Korean Wood Science and Technology
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• 제32권4호
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• pp.58-65
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• 2004

본 연구는 능이(Sarcodon aspratus)로부터 protease를 분리, 정제하고 이의 효소적 특성을 구명하고자 실시하였다. 정제가 진행되어감에 따라 protease의 비활성은 점차 증가하였는데, 탈염에 의해 비활성이 2.62배 증가하였으며, CMC column 처리로 17배, DEAE-Sephadex A-50 column 처리로 113.8배, Sephadex G-75 column 처리로 728.3배로 증가됨을 알 수 있었다. SDS-PAGE 전기영동 결과, single band의 분자량 약 43,000의 단백질임을 알 수 있었다. 최적 pH 3.5 부근의 정제 protease은 pH 4.35 및 pH 4.7의 등전점을 달리하는 protease가 확인되었으며, 이들 fraction의 비활성은 각각 3,025배 및 3,257배였다. 이들 효소들은 등전점만 다를 뿐, 효소적 특성이 거의 동일하였다. 이 protease는 pH 4에서 최적의 활성을 보였으며, pH 4~7의 범위에서 안정한 활성을 나타냈다. 이 protease의 최적 온도는 40~50℃ 범위였으며, 온도안정성을 조사한 결과, 60℃ 이상의 온도에서 급격한 활성저하를 나타내었다. 50℃에서는 80% 정도의 활성이 유지되었으며, 60℃로 온도가 올라가면 45%, 70℃에서는 거의 활성이 나타나지 않을 정도로 미미하였고, 80℃ 이상에서는 활성이 완전히 잃어버리게 됨을 알 수 있었다. 열에 대한 안정성에 있어서는 30℃ 및 40℃에서 1 h 열처리에서는 매우 안정한 활성을 보였으며, 50℃에서도 70 min간 처리로 90%의 안정성을, 60℃ 및 70℃에서는 10~20 min 처리로 급격한 효소의 활성저하가 시작되었으며, 70℃에서 30 min 처리로 효소의 활성이 없어짐을 알 수 있었다.

• 한국응용과학기술학회지
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• 제10권2호
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• pp.81-90
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• 1993

The Surfactants composed of acylated aterocollagen which is produced by the acylation of the side chain amino radicals of aterocollagen with an aliphatic acid having 12 to 18 carbon atoms will be discussed in this study. This condensation is done at moderate reaction temperature (<$25^{\circ}C$) in aqueous alkaline solution. The products of this reaction were identified by UV/VIS spectroscopy and infrared spectroscopy. For these compounds, surface active properties and physical properties including isoelectric point, Krafft point, surface tension, critical micelle concentration(cmc), foaming power, viscosity behaviour, water holding capacity, skin irritation and emulsifying power were measured respectively. The experimental results received that the products have a good emulsifying power, excellent water holding capacity while having low skin irritation. Thus, these derivatives will be expected to be used as an emulsifying agent for O/W type cosmetic emulsion.

• 한국연초학회지
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• 제18권1호
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• pp.39-48
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• 1996

A storage protein(SP-2) was confirmed in haemolymph during larval-pupal-adult development of tobacco burdworm(Helicoverpa assulta Guenee), and its biochemical characteristics were investigated. The titer of SP-2 showed a peak at mature larva, decreased gradually through the late pupal stage, and became undetectable at adult period. As the results from electrophoretic mnysis, SP-2 was confirmed to be glycolipoprotein(M.W. 332kDa) relatively stable to heat( $\leq$ 68$^{\circ}C$ ). This storage protein was determined to be a tetramer composed of a single subunit with MW of 83kDa, and the isoelectric point was 5.7. The amino acid composition of the SP-2 was characterized. It has relatively high content of methionine and histidine, whereas the contents of tyrosine and phenylalanine were relatively low.

• 대한본초학회지
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• 제22권4호
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• pp.21-28
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• 2007

Objectives : Kyenegum has been popularly used long as the digestive. The purpose of this study was to investigate the purification and characteristics of protease obtained from Kyenegum crude enzyme. Methods : Kyenegum protease was purified by precipitation with ammonium sulfate followed by SP-Spharose ion exchange chromatography. The molecular weight of Kyenegum protease was estimated by SDS-PAGE electrophoresis. Results : Kyenegum protease was 3,087 units/mg protein specific activity, 14.5 purification fold and 9.8 % recovery. The molecular weight of protease was estimated to be 18 kDa. The isoelectric point was pI 8.97 and values of Km and Vmax of its were 48 mg/mL and 2 units/min, respectively. Conclusion : The result suggests that the protease obtained from Kyenegum has excellent stability of temperature, acid and collagen substrate specificity.

• Animal cells and systems
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• 제13권3호
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• pp.345-350
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• 2009

We have isolated and characterized a new insect chicken type (c-type) lysozyme gene from the common cutworm, Spodoptera litura. The full-length cDNA of Spodoptera lysozyme is cloned by rapid amplification of cDNA ends PCR (RACE-PCR). The isolated cDNA consists of 1039 bp including the coding region for a 142-amino acid residue polypeptide, which included a signal peptide of 21-amino acid residue and a mature protein of 121-amino acid residue. The predicted molecular weight of mature lysozyme and its theoretical isoelectric point from amino acid composition is 13964.8 Da and 9.05, respectively. The deduced amino acid sequence of Spodoptera lysozyme gene shows the highest similarity (96.7%) to Spodoptera exigua lysozyme among other lepidopteran species. Amino acid sequence comparison with other the c-type lysozymes, Spodoptera lysozyme has the completely conserved $Glu^{32}$ and $Asp^{50}$ of the active site and eight Cys residues are completely conserved in the same position as that of other lepidopteran lysozymes.

• 한국식품영양학회지
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• 제9권3호
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• pp.319-324
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• 1996

The functional properties of protein recovered from red crab (Chitinonecetes opiiie) processing in water (RCP) were examined and compared with those of soybean protein isolate at pH 2~10 in water and NaCl solu5ion. The solubilities of RCP and SPI were miniumu at pH 4, the isoelectric point and increased significantly at lower or higher than pH 4. Solubilities in NaCl solution for both proteins decreased with incr NaCl concentration increase at all pH ranges. Emulsion capacity for both proteins was also minimum at pH 4 and increased as protein concentration increased from 2 to 6%. Emulsion capacity of RCP was higher than these of SPI at pH 6∼10 and all protein concentrations. Emulsion stability showed a similar trend to that of emulsion capacity. RCP had higher oft absorption capacity and lower water absorption capacity than SPI.

• Journal of Microbiology and Biotechnology
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• 제6권6호
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• pp.402-406
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• 1996

Inulin fructotransferase (depolymerizing) (EC 2.4.1.93) was purified 34-fold from the culture broth of Arthrobacter sp. A-6 by using a combination of ammonium sulfate fractionation, DEAE-Sepharose CL-6B chromatography and Sephacryl S-200 gel filtration. The purified enzyme converts inulin into di-D-fructofuranose dianhydride III(DFA III) and small quantities of fructo-oligosaccharides. The temperature and pH optima of the enzyme were $70^{\circ}C$ and 6.0, respectively. Molecular weight of the enzyme was determined to be 49 kDa by 12$%$ SDS-polyacrylamide gel electrophoresis, and 145 kDa by Sephacryl S-200gel filtration. This indicates that the functional inulin fructotransferase of Arthrobacter sp. A-6 has a homomeric trimer structure. The enzyme had an isoelectric point of pH 4.6. The N-terminal amino acid sequence of the purified enzyme subunit was Ala-Asp-Asn-Pro-Asp-Gly(\ulcorner)-Ser-Asn-Met(or Glu)-Tyr-Asp-Val.

• 한국식품저장유통학회지
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• 제17권4호
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• pp.435-443
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• 2010

Physicochemical and functional properties of collage from skate skin (Raja Kenojei) are examined depending on pH and NaCl concentration in the medium. The solubility decreased as NaCl concentration increased but, turbidity increased as concentration of collagen increased. Oil-holding capacity and water-holding capacity were similar to other fish skin collagens. Emulsion activity, creaming stability, and viscosity were lowest at where pH levels were isoelectric point regions of collagens. However, the higher pH values at 7.0-9.0 caused increasing foam expansion, foam viscosity, and gel strength. These results indicated that collagen from skate skin could be used as a functional ingredient for food and industrial applications.