• 제목/요약/키워드: artificial polypeptide

검색결과 8건 처리시간 0.027초

Synthesis of $\alpha$-L-Aspartyl-L-phenylalanine Methyl Ester from an Artificial Polypeptide

  • Choi, Soon-Yong;Kim, Hyun-Soo;Lee, Se-Yong
    • Journal of Microbiology and Biotechnology
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    • 제2권1호
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    • pp.1-6
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    • 1992
  • The aspartame, $\alpha$-L-aspartyl-L-phenylalanine methylester, is an artificial sweetener. Taking advantage of the fact that the aspartame is a derivative of dipeptide, synthesis of aspartame from the artificial polypeptide made by an artificial gene has been attempted. The artificial polypeptide (LAP32), a polymer of tripeptide (aspartyl-phenylalanyl-lysine), was purified from the E. coli cells harboring a recombinant plasmid containing the artificial gene. This polypeptide was then digested with trypsin and carboxypeptidase B to produce dipeptide (Asp-Phe). Using the esterase activity of $\alpha$-chymotrypsin, the dipeptide was directly converted into Asp-Phe methylester in a water-methanol system. When the methanol concentration in reaction mixture was 25%, 50% of dipeptide was converted to the dipeptide methylester without producing any by-products.

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온도 감응성 폴리펩티드로 표면 처리된 충전층의 유동 특성 (Flow Characteristics of Elastin-Like Polypeptide(ELP) Coated Packed Bed)

  • 김덕종;이종환;박상진;현진호
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2007년도 춘계학술대회B
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    • pp.3187-3190
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    • 2007
  • Elastin-Like polypeptide (ELP) composed of elastin-based repeating units is an artificial biomaterial which is biocompatible and non-immunogenic. ELP shows a characteristic inverse phase transition between hydrophobic and hydrophilic phase by external stimuli such as salt, pH and temperature. In this study, ELP coated PS (polystyrene) beads are packed in tubing and the thermo -responsive flow characteristics of the packed bed are investigated. Preliminary test results show that the control of the fluid flow can be achieved by using the temperature driven phase transition effect of the ELP coated beads in a microchannel.

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SYNTHESIS OF BLOCK COPOLYMERS CONTAINING POLYPEPTIDE AND ITS BIOMEDICAL APPLICATION

  • Cho, Chong-Su
    • 한국잠사학회:학술대회논문집
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    • 한국잠사학회 1997년도 Progress and Future Development of Sericultural Science and Technology 40th Anniversary Commemoration Symposium
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    • pp.159-169
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    • 1997
  • ABA-type(or AB) block copolymers composed of poly(${\gamma}$-alkyl L-glutamate) (PALG)[or poly(L-leucine)] as the A component and polyether[or poly (N-isopropy1 acrylamide) as the B component were synthesized by polymerization of (${\gamma}$-alkyl L-glutamate N-carboxyanhydride initiated by primary amined located at both(or one) ends of the polymer chains. Structural studies of the block copolymers were performed in the solution and solid state. Also, artificial skin, drug delivery system of the block copolymers and cell attachment onto the copolymer were carried out for biomedical applications.

호남지방의 닭 Leucocytozoon증에 관한 연구 (Studies on leucocytozoonosis of chickens in Honam districts)

  • 임병무;서민석;이재구;이주묵;김영진;최인열;한규삼
    • 대한수의학회지
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    • 제34권1호
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    • pp.135-139
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    • 1994
  • 1992-1993년 호남지방의 4개 양계장에서 처음으로 닭의 Leucocytozoon caulleryi 자연감염증을 보이는 87수를 검색하였는데, 임상증세와 혈액내 merozoite 및 gametocyte 검출 그리고 내장기관으로부터 schizont의 발견으로 본 질병을 확증할 수 있었다. 본 감염증은 일년 중 6월 하순부터 9월 중순까지에 발견되었으며, 자연감염된 혈액(merozoite포함)을 미감염된 닭에 접종하여 인공감염상을 볼 수 있었다. 자연감염후 회복된 닭중 1수는 12월에 간에서, 또 다른 1수는 다음해 2월에 심장 근육에서 schizont가 발견되어 본 감염증의 재발이나 동절기를 지나는 장기간 감염 가능성을 보여 주었다. 본 원충의 gametocyte 추출물에서 특이 항원 항체 반응을 보이는 polypeptide는 50.1kD이었다.

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Heterologous Expression of Daptomycin Biosynthetic Gene Cluster Via Streptomyces Artificial Chromosome Vector System

  • Choi, Seunghee;Nah, Hee-Ju;Choi, Sisun;Kim, Eung-Soo
    • Journal of Microbiology and Biotechnology
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    • 제29권12호
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    • pp.1931-1937
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    • 2019
  • The heterologous expression of the Streptomyces natural product (NP) biosynthetic gene cluster (BGC) has become an attractive strategy for the activation, titer improvement, and refactoring of valuable and cryptic NP BGCs. Previously, a Streptomyces artificial chromosomal vector system, pSBAC, was applied successfully to the precise cloning of large-sized polyketide BGCs, including immunosuppressant tautomycetin and antibiotic pikromycin, which led to stable and comparable production in several heterologous hosts. To further validate the pSBAC system as a generally applicable heterologous expression system, the daptomycin BGC of S. roseosporus was cloned and expressed heterologously in a model Streptomyces cell factory. A 65-kb daptomycin BGC, which belongs to a non-ribosomal polypeptide synthetase (NRPS) family, was cloned precisely into the pSBAC which resulted in 28.9 mg/l of daptomycin and its derivatives in S. coelicolor M511(a daptomycin non-producing heterologous host). These results suggest that a pSBAC-driven heterologous expression strategy is an ideal approach for producing low and inconsistent Streptomyces NRPS-family NPs, such as daptomycin, which are produced low and inconsistent in native host.

담배식물체에서 필수아미노산인 lysyl-glutamyl-tryptophan을 암호화하는 인공유전자의 발현 (Expression of an artificial gene encoding a repeated tripeptide lysyl-g1utamyl-tryptophan in Tobacco Plant)

  • 이수영;나경수;백형석;박희성;조훈식;이용세;최장원
    • 생명과학회지
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    • 제12권1호
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    • pp.96-105
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    • 2002
  • 식물 단백질의 영양가 향상을 위한 일환으로 필수아미노산의 조성이 풍부한 인공단백질을 암호화하는 인공유전자를 담배 식물체에서 발현을 시도하기 위하여, 식물에서 외래유전자의 발현에 널리 사용되는 Cauliflower mosaic virus (CaMV)의 35S promoter를 이중으로 중첩되도록 하고, (Lys-Glu-Trp)이 64번 반복되는 인공유전자 및 nopaline synthase (nos) terminator를 갖고있는 binary vector pART4-4를 구성하였다. 이 재조합 플라스미드는 Agrobacterium tumefaciens를 이용한 형질전환에 의해 Nicotiann tabacum (Var. Xanthi)으로 도입되었다. Kanamycin이 포함된 신초 유도 배지 및 뿌리 유도배지를 이용하여 정상적으로 재생된 담배 식물체로부터 도입된 인공유전자의 발현을 분석하였다. 추출한 genomic DNA를 EcoRI으로 자른 다음 Southern blot 분석에 의하면, 효소 절단 시 예상되는 1.1 kb에서 band를 형성하였으며 각각의 형질전환 식물체에 인공유전자가 1 또는 3 개씩 도입되어 있음을 확인하였다. Northern blot 분석에 의하면 약 1.2 kb 전사체가 비교적 안정하게 발현되었으며, 잎, 줄기, 뿌리로부터 RNA를 분리하여 promoter의 조직 특이성 발현을 분석한 결과, 잎에서 생성되는 RNA가 줄기나 뿌리 조직보다 안정하게 발현되었다. 형질전환 식물체에서 Western blot에 의한 단백질 분석 결과, 잎에서 추출한 단백질로부터 원하는 크기인 33 kDa의 인공단백질이 생성됨을 확인하였으며 발현 수준은 전체 세포 단백질의 0.1%로서 낮은 수준이었다.

Expression and Purification of an ACE-Inhibitory Peptide Multimer from Synthetic DNA in Escherichia coli

  • OH, KWANG-SEOK;YONG-SUNG PARK;HA-CHIN SUNG
    • Journal of Microbiology and Biotechnology
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    • 제12권1호
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    • pp.59-64
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    • 2002
  • An angiotensin I-converting enzyme (EC 3.4.15.1) (ACE), which can convert inactive angiotensin I into angiotensin II, a vasoconstrictor, is one of the key enzymes in controlling hypertension. It is suggested that the inhibition of ACE prevents hypertension, and many inhibitory peptides have already been reported. In the current study, oligonucleotides encoding ACE inhibitory peptides (IY, VKY) were chemically synthesized and designed to be multimerised due to isoschizomer sites (BamHI, BglII). The cloned gene named AP3 was multimerised up to 6 times in pBluescript and expressed in BL2l containing pGEX-KG. The fusion protein (GST-AP3) was easily purified with a high recovery by an affinity resin, yielding 38 mg of synthetic AP3 from a 1-1 culture. The digestion of AP3 by chymotrypsin exhibited an $IC_50$ value of $18.53{\mu}M$. In conclusion, the present experiment indicated that AP3 could be used as a dietary antihypertensive drug, since the potent ACE inhibitory activity of AP3 could be activated by chymotrypsin in human intestine.

Effect of Serum IGF-I on Progesterone Concentration during Early Pregnancy in Korean Native Cattle (Hanwoo)

  • Ryu, Yang-Hwan;Yang, Jong-Yong;Seo, Dong-Sam;Ko, Yong
    • Asian-Australasian Journal of Animal Sciences
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    • 제16권2호
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    • pp.176-179
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    • 2003
  • Insulin-like growth factor-I (IGF-I) is a polypeptide that has the function of regulating the expression of steroid hormones through endocrine, paracrine, and autocrine actions in reproductive organs. Moreover, IGF-I is involved in ovulation, implantation, maintenance of pregnancy, and development of fetuses in animals. Therefore, this study was conducted to investigate the effects of serum IGF-I concentration on progesterone ($P_4$) concentration and pregnancy rates in Korean native cattle (Hanwoo). Blood was collected at estrus (Day 0) and Day 11. Artificial insemination was performed at Day 0. Serum IGF-I and $P_4$ concentrations were measured by radioimmunoassay (RIA). Overall, $P_4$ concentration was higher at Day 11 than Day 0, whereas the pattern of IGF-I concentration was reversed. When animals were divided into two groups depending on the pregnancy status, $P_4$ concentrations of the pregnant group was significantly higher than that of the non-pregnant group at Day 0 (p<0.05) and Day 11 (p<0.05). But, lower IGF-I concentrations were detected in the pregnant group at Day 0 (p<0.05) and Day 11 (p<0.05) compared to the non-pregnant group. In conclusion, these results indicated that serum IGF-I is inversely associated with $P_4$ concentration during early pregnancy in Hanwoo.