• Proceedings of the Korean Society of Toxicology Conference
• /
• 2003.10b
• /
• pp.87-88
• /
• 2003

PegIntron is the pegylated form of human recombinant interferon alfa-2b (IFN${\alpha}$2b). IFN ${\alpha}$2b, known as Intron A, has been in approved clinical use since the 1980's for various cancer indications, and for the treatment of Hepatitis C. In the mid 1990's, several clinical investigators reported that combination therapy with ribavirin and Intron A dramatically increased the therapeutic efficacy for treatment of Hepatitis C.(omitted)

• Journal of the Korean Ceramic Society
• /
• v.33 no.10
• /
• pp.1163-1169
• /
• 1996

The effects of borax on the phase formation of C2S, C4A3 and $\alpha$'-C2S phases. It has negative effects on formation of C4A3 And it lowers the forming temperature of C4AF. It also has been found that borax improves the clinkerization of MBC. In the MBC clinker with borax 3% C2S have larger and more irregular shapes, larger C/S mole ratio and C4A3 have smaller size larger C/ molr ratio than in the clinker without borax.

• Journal of the Korean Chemical Society
• /
• v.44 no.1
• /
• pp.37-44
• /
• 2000

In order to develope bioactive substances, dried fmit body of Daedalea dickinsii collected from Taeback mountain was extracted with ethanol, The compounds 1 and 2 were purified by solvent extraction, silica gel column chromatography and recrystallization from the ethanol extracts. Melting point, molecular weight and molar extinction coefficient of the compound 1 were estimated to be $167{\sim}168^{\circ}C$, 572 and 5,040 at 208 nm. The structure of this compound 1 has been elucidated to be 24S, 25S, $3{\alpha}-carboxyacetylquercinic$ acid using spectroscopic properties. This compound showed antibiotic activities against fungi, yeasts and bacteria and it also showed anticancer activity $IC_{50}=64.5\;{\mu}M$) against Korean stomach cancer cell. Melting point, molecular weight and molar extinction coefficient of the compound 2 were estimated to be $233{\sim}235^<\circ}$, 572 and 5,080 at 208 nm. The structure of this compound was elucidated to be 24S, 25R, $3{\alpha}-carboxyacetylquercinic$ acid. The compound 2 showed different antibiotic activities with the compound 1.

• Microbiology and Biotechnology Letters
• /
• v.14 no.3
• /
• pp.209-212
• /
• 1986

$\alpha$-Amylase gene of Bacillus amyloliquetaciens was cloned on plasmid YEp13, S. cerevisiae-E. coli shuttle vector. Hybrid plasmid pTG17, carrying $\alpha$-amylase gene of B. amyloliquefaciens, was transformed to E. coli and the expression of it in yeast was investigated. This plasmid was unstable in E. coli and produced two minor plasmids, pTG17-1 and PTG17-2, which resulted from the segregation of it. Transformant of S. cerevisiae MC16 with pTG17-1 plasmid was not appeared on SD medium because of the Leu2 gene defection. S. cerevisiae could be transformed by the hybrid plasmid, and $\alpha$-amylase activity of the yeast transformant was detected by somogyi-Nelson method and agar diffusion method.

• Korean Journal of Microbiology
• /
• v.35 no.4
• /
• pp.315-321
• /
• 1999

This study has been performed to deveope a yeast strain having high ${\alpha}$-amylase production ability using nuclear transfer method. Hybrids formed between the strains of Saccharomyces fiburigera KCTC 7393 and Saccharomyces cerevisiae KCTC 7049 (tyr-, ura-)were obtained by nuclear transfer technique. Nuclei isolated from the wild type S. fiburigera strain were transfered into auxotrophic mutants S. cerevisiae and selected the hybrids showing an increased starch degrading capability were selected (MN-16). This transformant grew best and produced maximal ${\alpha}$-amylase activity on the medium containing 2% (V/V) soluble starch. ${\alpha}$-Amylase from MN-16 was purified electrophoretically homogenety and its properties were investigated. The enzyme was purified about 10.6 fold with an overall yield 9.7% from the culture medium by ammonium sulfate fractionation. DEAE-Sephacel column chromatography, and Sephacryl S-200 column chromatography. The purified enzyme showed a single band on SDS-polyacrylamide gel electrophoresis. The molecular weight of the ${\alpha}$-amylase was estimated to be 53,000 daltons by SDS-PAGE and by gel permeation chromatography on Sephacryl S-200. The purified enzyme showed the maximum activity at pH 5.5 and 40${\circ}C$. The km value for soluble starch was 2.5㎎/㎖. The enzyme activity increased in the presence of $Ca^{2+}, Co^{2+}, EDTA, Mg^{2+}, Mn^{2+}, Zn^{2+}$, but inhibited by $Cu^{2+}, Fe^{2+}$, and $Ni^{2+}$

• Polymer(Korea)
• /
• v.24 no.5
• /
• pp.646-655
• /
• 2000

Polymerizations of higher $\alpha$-olefins were carried out in toluene by using highly isospecific catalyst, rac-(EBI)M(NMe$_2$)$_2$ (EBI=1,2-ethylenebis-(1-indenyl); M=Zr(rac-1); M=Hf(rac-2)) In the presence of Al(i-Bu)$_3$/[Ph$_3$C][B($C_{6}F_{5}$)$_4$]. The polymerization of high $\alpha$-olefin showed high activity and similar polymerization behavior. The polymerization activity was affected by both monomer size and lateral size of polymer chain. The conversion of monomer to polymer decreases with the increased lateral size in the order of 1-pentene>1-hexene>1-octene>1-decene. The same dependences of melting behavior and intrinsic viscosity of polyolefin on lateral size were observed according to the results obtained by differential scanning calorimetry and intrinsic viscosity. All poly($\alpha$-olefin)s showed very high isotacticity (triad) and the isotacticity increases in the order of poly(1-pentene)$^1H$ NMR and Raman spectra analysis showed that chain transfer to cocatalyst, which generates saturated methyl groups, Is a main chain termination. The $\beta$-hydride eliminations, which generate unsaturated vinylidene, tri-substituted, and vinylene end group. are found to be minor chain terminations.

• Microbiology and Biotechnology Letters
• /
• v.32 no.1
• /
• pp.29-36
• /
• 2004

$\alpha$-Cyclodextrin glucanotransferase excreted from a newly isolated Geobacillus thermosacchalytycus was purified through the ultrafiltraion, hydrophobic Sepharose CD-4B affinity chromatography, and gel filtration on Sephadex G-75, respectively. The molecular weight of the purified CGTase was 69 kDa and its N-terminal amino acid sequence was determined to be Asn-Leu-Asn-Lys-Val-Asn-Phe-Val-Ser-Asp-Val-Val-Val-Gln-Ile. The optimum pH and temperature were pH 6.0 and$ 60^{\circ}C$, respectively, and stably at the pH range of 6.0-8.0 and $60^{\circ}C$ in the presence of $Ca^{++}$. The excreted CGTase from the thermophilic G. thermosacchalytycus was $\alpha$-type showing a high coupling activity for the transglycosylation on various glucosides. The coupling reaction was carried out according to the random ternary complex mechanism.m.

• Journal of Microbiology and Biotechnology
• /
• v.19 no.12
• /
• pp.1506-1513
• /
• 2009

$\alpha$-Dextranase, which can hydrolyze dextran, is largely used in the sugar industry. However, a thermostable $\alpha$-dextranase is needed to alleviate the viscosity of syrups and clean blocked machines. Thus, to improve the optimal temperature of Lipomyces starkeyi $\alpha$-dextranase expressed by Pichia pastoris, the rational introduction of a de novo designed disulfide bond was investigated. Based on the known structure of Penicillium minioluteum dextranase, L. starkeyi $\alpha$-dextranase was constructed using homology modeling. Four amino acids residues were then selected for site-directed mutagenesis to cysteine. When compared with the wild-type dextranase, the mutant DexM2 (D279C/S289C) showed a more than $13^{\circ}C$ improvement on its optimal temperature. DexM2 and DexM12 (T245C/N248C, D279C/S289C) also showed a better thermal stability than the wild-type dextranase. After the introduction of two disulfide bonds, the specific activity of DexM12 was evaluated and found to be two times higher than that of the wild-type. Moreover, DexM12 also showed the highest $V_{max}$.

• Applied Biological Chemistry
• /
• v.41 no.7
• /
• pp.489-495
• /
• 1998

The optimum culture condition of Scopulariopsis brevicaulis for the production of ${\alpha}$-galactosidase was as follows: Tryptone 1.5%, $NH_4NO_3$ 0.2%, Raffinose 2.5%, $KH_2PO_4$ 0.5%, yeast extract 0.5%, pH 7.0, $27^{\circ}C$. The optimum pH and temperature for the enzyme activity of ${\alpha}$-galactosidase producing Scopulariopsis brevicaulis were pH 7.0 and $27^{\circ}C$, respectively. The enzyme was relatively stable at $pH\;6.0{\sim}8.0$ and at temperature below $40^{\circ}C$. The activity of the enzyme was inhibited by $Ag^{2+},\;Hg^{2+},\;Cu^{2+}$, p-chloromercuribenzoic acid and Iodine. These results would indicate the presence of -SH groups in the catalytic site of the enzyme. Km value was 1.9 mM for $p-nitrophenyl-{\alpha}-D-galactopyranoside$ and Vmax value was $9.66{\times}10^2\;{\mu}M/min$. Sugar constituents of culture broth were identified by HPLC that the enzyme liberated sucrose, glucose and fructose from raffinose and raffinose was significantly decreased.

• The Mathematical Education
• /
• v.26 no.2
• /
• pp.55-61
• /
• 1988

이 논문에서는 CS-Semistratifiable 공간보다 더 일반화된 공간 Cn-Semistratifiable을 정의 하며 그에 따른 여러가지 성질들을 조사하였다. 위상 공간(X, $\tau$)에 대하여 $\alpha$$\times$$\tau$에서 X의 폐집합족으로의 함수 S가 존재하여 다음 조건들을 만족할 때 공간X는 Cn-Semistratifiable over $\alpha$라 정의한다. a) 임의의 개집합 U에 대하여 U=U{S($\beta$, U) : $\beta$<$\alpha$} b) U, V가 X의 개집합이고 U⊂CV이면 모든 $\beta$<$\alpha$에 대하여 S($\beta$, V)⊂S($\beta$, V)이다. c) 만약 ${\gamma}$<$\beta$<$\alpha$ 이라면 임의의 개집합 U에 대하여 S(${\gamma}$, U)⊂S($\beta$, U)이다. d) X의 수렴하는 net $X_{\beta}$$\longrightarrow$X와 X를 품는 임의의 개집합 U에 대하여 적당한 $\beta$<$\alpha$가 존재하여 X$\in$S($\beta$. U)이고 { $X_{\beta}$}는 S($\beta$, U)안에 eventual하게 들어간다. 위의 정의에 의하여 다음과 같은 성질들이 증명되었다. 1 . Strstifiable over $\alpha$$\longrightarrow$cn-semistratifiable over$\longrightarrow$semistratifiable over $\alpha$ 2, 어떤 공간이 cn-Semistratifiable over $\alpha$이기 위한 필요충분 조건은 그것이 linearly cushioned cn-pairnet를 갖는 것이다. 3. cn-semistratifiable over $\alpha$의 부분공간 역시 cn-semistratifiabie over $\alpha$ 하다. 4. on-semistratifiable over $\alpha$의 유한개의 적공간 역시 cn-semistratifiabie over $\alpha$한다. 5. 폐 cn-semistratifiable over $\alpha$ 부분공간들의 합공간 역시 on-semistrbtifiable over $\alpha$ 하다. 6. 폐연속 net-cevering 함수에 의하여 cn-semistratifiable over $\alpha$ 성질이 보존된다.