• 대한의생명과학회지
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• 제9권4호
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• pp.203-207
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• 2003

Protein aggregation could be problematic as causes of diseases and hindrance in the production of useful recombinant proteins. Aggregation of mutant tryptophan synthase $\alpha$-subunits was examined by treatment with urea and at high temperature. Large amorphous aggregate seemed to appear by heat treatment, while more various aggregates in size were formed by treatment with urea at low concentration. The result indicates that different aggregate in size could be formed depending on the treatment condition, suggesting different mechanisms underlying aggregation processes.

• 한국미생물·생명공학회지
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• 제25권2호
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• pp.173-177
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• 1997

Glycerol-3-phosphate cytidylyltransferase from Bacillus subtilis was modified with various chemical modifiers to determine the active sites of the enzyme. Treatment of the enzyme with group-specific reagents diethylpyrocarbonate, N-bromosuccinimide, or carbodiimide resulted in complete loss of enzyme activity, which shows histidine, tryptophan, and glutamic acid or aspartic acid residues are at or near the active site. In each case, inactivation followed pseudo first-order kinetics. Inclusion of glycerol-3-phosphate and/or CTP prevented the inactivation, indicating the presence of tryptophan and glutamic acid or aspartic acid residues at the substrate binding site. Analysis of kinetics of inactivation showed that the loss of enzyme activity was due to modification of a two histidine residues, single tryptophan residue, and two glutamic acid or aspartic acid residues.

• 한국미생물·생명공학회지
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• 제17권2호
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• pp.85-87
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• 1989

토양으로부터 분리한 Xylose 발효효모 X-6-41 (Candida sp.)의 xylanase 효소생성 조건을 조사해 본 결과, 본 실험에 사용한 X-6-41 균주는 배지조성중 yeast extract 혹은 polypeptone이 첨가되면 xylanase 효소생성이 없었다. 즉 특정 아미노산인 isoleucine에 의해서는 그 생성이 억제되었고, tryptophan 25$\mu$g/$m\ell$ 농도의 존재하에서는 xylanase 생성이 증가했다.

• 한국식품조리과학회지
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• 제12권1호
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• pp.108-114
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• 1996

The study was carried out to compare the reaction rate of Maillard browning reaction of 2 dipeptides (Leucylglycine, Tryptophylglycine) and 4 amino acids (Lysine, Glycine, Leucine, Tryptophan) with xylose heated for 0∼24 hours at 60∼100$^{\circ}C$. 1. The color intensity of the browning mixture heated at 100$^{\circ}C$ for 24 hours was the highest in tryptophanxylose, and in order to tryptophylglycine-xylose > lysine-xylose > leucylglycine-ylose > leucine-xylose > glycine-xylose. 2. The reaction rate constants (k) determined from the browning pigment concentrate with time were similar to the result of the color intensity, that is, the k were the highest in the tryptophan-xylose. 3. The residual amounts of dipeptides, amino acids and xylose in the browning mixture diminished as the browning temperature increase. 4. The activation energies (Ea) calculated from k were the highest in leucine-xylose (143.72 J/mol) and the lowest in tryptophan-xylose (117.45 J/mol). The range of Q$\sub$10/ values were 2.84∼3.58.

• 생약학회지
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• 제4권1호
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• pp.1-7
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• 1973

Recent findings that agroclavine strongly inhibits: lactation and that ergocornine and ergonovine induce regression or inhibition of pituitary tumor growth in rats revealed new pharmacological activities in addition to the well-known activities of ergot alkaloids. Clavicipitic acid, isochanoclavine (I) and chanoclavine (II) are newly isolated alkaloids. It was already established that tryptophan, mevalonic acid and methionine are biosynthetic precursors of ergoline, a basic structure of the alkaloids, which is formed via $4-({\gamma},{\gamma}-dimethylallyl)-tryptophan$, mediated by dimethylallylpyrophosphate: tryptophan dimethylallyl transferase. Chanoclavine-I appears to be an intermediate to agroclavine which is converted to elymoclavine. Agroclavine and elymoclavine were also found to be hydroxylated by peroxidase to setoclavine and penniclavine, respectively. Elymoclavine is converted to ergotamine and lysergic acid ${\alpha}-hydroxyethylamide$, respectively. Pyruvate and alanine were found to be incorporated into the two-carbon unit of the ${\alpha}-hydroxyethyl$ moiety of the latter. Lysergylalanine is converted to ergometrine, but not to lysergic acid ${\alpha}-hydroxyethylamide$.

• 생명과학회지
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• 제14권1호
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• pp.14-16
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• 2004

트립토판 합성효소의 이소조절성에 작용하는 리간드가 알려져 있다. $\beta$반응의 기질인 세린만이 있는 조건에서 일가 양이온과 glycerophosphate의 리간드효과를 잔기치환체를 사용하여 조사하였다. 이들 리간드가 이 효소의 이소조절성에 관여하고 있음을 보여주고 있다.

• Natural Product Sciences
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• 제7권4호
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• pp.107-109
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• 2001

To investigate anti-diabetic component from the node of lotus rhizome (Nelumbo nucifera; Nymphaeaceae), activity guided isolation was conducted. One amino acid was isolated from active fraction of the aqueous methanolic extract. The structure of this compound was identified as tryptophan (1) by the analysis of spectroscopic evidences and comparisons with the data of authentic samples. Tryptophan reduced the blood glucose level significantly in glucose-fed hyperglycemic mice compared with glucose-treated group and exhibited 44.3% of activity compared with tolbutamide,.

• 생명과학회지
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• 제9권3호
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• pp.328-332
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• 1999

The effect of cations on the formation of protein aggregates was examined by in vitro refolding of mutant tryptophan synthase $\alpha$-subunit in which Pro 24 was replaced by Leu. $NH^{4+},; K{^+}; and; Na^{+}$ and no effect, but $Mg^{2+}; and; Ca^{2+}$stimulated the formation of protein aggregates in dose-dependent manner. It is suggested that $Mg^{2+} and Ca^{2+}$ may be implicated in the formation of protein aggregates in vivo.

• Journal of Microbiology and Biotechnology
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• 제11권5호
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• pp.798-803
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• 2001

Peptide synthetases produced from various microorganisms are multifunctional enzyme complexes and their substrates are recognized and activated by adenylation domains. To identify the substrate specificity of the peptide synthetase isolated from Bacillus subtilis 713, known to produce an antifungal peptide, two adenylation domains containing the minimal functional portion were expressed and purified. ATP-ppi exchange experiments and kinetic studies revealed that the two adenylation enzymes had a substrate specificity to $_{L}-lysine{\;}and{\;}_{L}-tryptophan$, respectively. In addition, based on a signature sequence comparison, the substrate of the third domain was predicted to be L-glutamic acid. These results suggest that this peptide synthetase is novel because there has been no previous report on a peptide synthetase that uses $_{L}-lysine,{\;}_{L}-tryptophan,{\;}and{\;}_{L}-glutamic$ acid as substrates in that order.

• 생명과학회지
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• 제23권2호
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• pp.319-323
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• 2013

단백질 덩어리는 질환의 원인이 되기도 하고, 유용한 유전자 재조합 단백질의 생산시 문제를 야기하기도 한다. 본 연구에서는 조건을 달리함으로 트립토판 합성효소 ${\alpha}$ 소단위체로부터 적어도 3가지 이상 다른 종류의 덩어리가 생길 수 있음을 보여주고 있다; (1) 불투명 흰색 침전 가능한 덩어리 (2) 투명하고 겔 유형의 침전 가능한 덩어리 (3) 불침전 덩어리. 이런 다른 종류의 덩어리 형태는 다른 기작을 통해 일어날 것으로 추정된다.