• 한국생명과학회:학술대회논문집
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• 한국생명과학회 2002년도 제38회 학술심포지움
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• pp.13-19
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• 2002

To elucidate the regulatory mechanism for expression of sialyl-glycoconjugates and their biological functions, ninetheen sialyltransferase cDNAs including eleven by our group or co-works have been cloned and characterized so far. The cloned sialyltransferases are classified into four families according to the carbohydrate linkages they synthesize: ${\alpha}2,3-sialyltransferase$ (ST3Gal I-VI), ${\alpha}$ 2,6-sialyltransferase (ST6Gal I), GalNAc ${\alpha}$ 2,6-sialyltransferase (ST6GalNAc I-VI), and ${\alpha}2,8-sialyltransferase$ (ST8Sia I-VI). Each of the sialyltransferase genes is differentially expressed in a tissue-, cell type-, and stage-specific manner. These enzymes differ in their substrate specificity and various biochemical parameters. However, enzymatic analysis conducted in vitro with recombinant enzyme revealed that one linkage can be synthesized by multiple enzymes. We present here an overview of structure and function of sialyltransferases performed by our group and co-works. Genomic structures and transcriptional regulation of two kinds of human sialyltransferase gene are also presented.

• Food Science and Biotechnology
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• 제14권2호
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• pp.259-262
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• 2005

A fraction (CMEx-AH-${\beta}$) of water-soluble polysaccharides, showing selective antitumor activities, was isolated from the mycelia of solid cultured Agaricus blazei Murill by hot-water extraction, ethanol precipitation, and series of chromatography. Chemical characteristics of CMEx-AH-${\beta}$, were as follows: carbohydrate content, 48%; monosaccharide composition, Man:Glu:Gal (2:93:5); molecular weight, $2{\times}10^5$; uronic acid content, 6.2%. Fundamental structure of CMEx-AH-${\beta}$, was deduced as ${\beta}-(1\;{\rightarrow}\;6)$-D-glucan with ${\beta}-(1\;{\rightarrow}\;3)$-D-glucosidic side chains based on results of methylation and $^{13}C$ NMR spectroscopic analyses.

• Food Science and Biotechnology
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• 제14권6호
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• pp.783-787
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• 2005

Fraction (PMEx-AH-${\beta}$) of water-soluble polysaccharide, showing stimulating activity against macrophages, was isolated from mycelia of solid cultured Phellinus linteus by hot-water extraction, ethanol precipitation, and chromatography. Chemical characteristics of PMEx-AH-${\beta}$ were as follows: carbohydrate content, 71%; monosaccharide composition, Man:Glu:Gal (9:64:27); molecular weight, $1-7{\times}10^4$; uronic acid content, 6.8%. Fundamental structure of PMEx-AH-${\beta}$ is deduced as ${\beta}$-($1{$\rightarrow}6$)-D-glucan with ${\beta}$-($1{\rightarow}3$)-D-glucosidic side chains based on methylation analysis.

• 한국생물물리학회:학술대회논문집
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• 한국생물물리학회 1999년도 학술발표회 진행표 및 논문초록
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• pp.35-35
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• 1999

Amylases catalyze the hydrolysis of starch material and play central roles in carbohydrate metabolism. The structure and a size exclusion column chromatography proved that the enzyme is a dimer in solution. The N -terminal segment of the enzyme folds into a distinct domain and comprises the enzyme active site together with the central (${\alpha}$/ ${\beta}$)$\sub$8/ barrel of the adjacent subunit.(omitted)

• Food Science and Biotechnology
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• 제18권3호
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• pp.667-671
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• 2009

Extract of water-soluble polysaccharide (CFWx), showing inhibiting activity on ${\alpha}-glucosidase$, was prepared from the fruiting bodies of Cordyceps militaris by hot-water extraction, and ethanol precipitation. Chemical characteristics of CFWx were as follows: carbohydrate content 30% including 16% of uronic acid; 51% protein content; monosaccharide composition, Man:Glu:Gal (30:43:27); molecular weight $3-5{\times}10^4$. CFWx was further purified by ion-exchange, gel-permeation, and affinity chromatography and $CFWx-AH-{\alpha}$ fraction was isolated. Fundamental structure of $CFWx-AH-{\alpha}$ was deduced as ${\alpha}-(1{\to}4$)-D-glucan with ${\alpha}-(1{\to}3$)- and/or ${\alpha}-(1{\to}6$)-D-glycosidic side chains based on methylation analysis.

• Bulletin of the Korean Chemical Society
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• 제18권4호
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• pp.415-424
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• 1997

Conformational flexibilities of the GlcNAc(β1,3)Gal(β)OMe are investigated through NMR spectroscopy and molecular modeling. Adiabatic energy map generated with a dielectric constant of 50 contains three local minima. All of the molecular dynamics simulations on three local minimum energy structures show fluctuations between two low energy structures, N2 at φ=80° and ψ=60° and N3 at φ=60° and ψ=-40°. We have presented adequate evidences to state that GlcNAc(β1,3)Gal(β)OMe exists in two conformationally discrete forms. Two state model of N2 and N3 conformers with a population ratio of 40:60 is used to calculate the effective cross relaxation rate and reproduces the experimental NOEs very well. Molecular dynamics simulation in conjunction with two state model proves successfully the dynamic equilibrium existed in GlcNAc(β1,3)Gal(β)OMe and can be considered as a powerful method to analyze the motional properties in the structure of carbohydrate. This observation also cautions against the indiscriminate use of a rigid model to analyze NMR data.

• 생명과학회지
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• 제31권2호
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• pp.219-222
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• 2021

본 연구에서는 저분자펩타이드로부터 유래되는 단백질을 확인하기 위해 갈색거저리의 유충, 번데기, 성충의 저분자 단백질체 분석을 수행하였다. 저분자 펩타이드 분석으로부터 유래된 54 단백질이 최종적으로 확인되었다. 확인된 단백질 중 성체에만 존재하는 단백질이 가장 높은 빈도로 존재하였고, 그 다음은 성체와 유충에 동시 존재하는 단백질이 높은 빈도로 탐색되었다. 그러나 번데기를 포함하는 그룹들은 모두 낮은 빈도로 감지되었다. 분석된 단백질에 orthologous classification의 결과에서 일반적 기능 예견만(general function prediction only) 보이는 단백질이 가장 높은 빈도로 조사되었다. 크로마틴 구조와 동적상태(chromatin structure and dynamics)에 연관된 단백질은 비교적 높은 빈도로 탐색되었다. 또한, 아미노산 수송과 물질대사(amino acid transport and metabolism) 및 탄수화물 수송 및 물질대사(carbohydrate transport and metabolism)와 연관된 단백질도 높은 빈도로 분석되었다. 그러나 뉴클레오타이드 수송 물질대사, 코엔자임 수송 및 물질대사, 세포외 구조, 모빌로좀(mobilome), 및 핵 구조와 연관된 단백질은 전혀 탐지되지 않았다. 따라서 크로마틴, 아미노산, 탄수화물 물질대사와 연관된 단백질들이 보다 쉽게 저분자 펩타이드로 전환되어 체액 중에 잔존될 수 있는 것으로 보이며, 이들 펩타이드들이 생리활성물질로써 기능을 수행할 수 있을 가능성이 높은 것으로 추정된다.

• Journal of the Korean Wood Science and Technology
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• 제42권2호
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• pp.183-192
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• 2014

For the structure determination of D-(+)-sucrose, which consists of ${\alpha}$-D-(+)-glucose and ${\beta}$-D-(+)-fructose, it was acetylated with acetic anhydride and triethyl amine, pyridine, zinc chloride, and sodium acetate as catalysts. The acetylated D-(+)-sucrose was acid-hydrolyzed using sulfuric acid and sodium chloride in methanolic solution. The structures of the reaction products were determined by $^1H$-NMR and $^{13}C$-NMR spectra. The yield of the acetylation indicated the high value in zinc chloride as 70% in zinc chloride catalyst. The acid-hydrolyzed product of the acetylated D-(+)-sucrose, 2,3,4,6,1',3',4',6'-octa-O-acetyl-D-(+)-sucrose, gave 2,3,4,6-tetra-O-acetyl-${\beta}$-D-(+)-glucose and it suggests that the acetylated D-(+)-sucrose was rearranged through the formation of oxonium ion by mutarotation in the 2,3,4,6-tetra-O-acetyl-${\alpha}$-D-(+)-glucose moiety and through the ring opening in the 1',3',4',6'-tetra-O-acetyl-${\beta}$-D-(+)-fructose moiety.

• 한국미생물·생명공학회지
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• 제33권1호
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• pp.9-15
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• 2005

Chitin deacetylase(CDA; EC 3.5.1.41)는 키틴의 N-acetamide bonds를 가수분해하여 이를 키토산으로 전환시키는 효소다. 한편, 키토산은 의약, 화장품, 식품, 농업 등의 분야에서 다양하게 응용되는 고분자 다당류이다. 본 논문에서는 미생물 유래 CDA의 분포, 분석법, 효소적 특성, 기질 특이성, 작용기작, 유전자의 구조, 생물학적 역할, 응용 등의 최신 지견을 기술하고자 하였다. 미생물 CDA가 세포벽 형성과 식물-미생물 상호작용에 관여한다는 연구결과들을 제시하였으며, CDA의 유전자 구조를 다양한 acetylated poly/oligo-saccharides를 탈아세틸화하는 family 4 carbohydrate esterase의 유전자 구조와 비교하였다. 키틴의 탈아세틸화로 키토산을 제조하는 과정에 CDA의 활용 가능성과, CDA를 포함한 고활성의 키틴 대사효소들을 분비하는 곤충 병원균의 활용 가능성도 살펴보았다.

• Asian Pacific Journal of Cancer Prevention
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• 제17권2호
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• pp.691-695
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• 2016

Protein glycosylation is the most common posttranslational modification in mammalian cells. Aberrant protein glycosylation has been reported in various diseases, including cancer. We identified and quantified the glycan structures of O-linked glycoprotein from cholangiocarcinoma (CCA) cell lines from different histological types and compared their profiles by nanospray ionization-linear ion trap mass spectrometry (NSI-$MS^n$). Five human CCA cell lines, K100, M055, M139, M213 and M214 were characterized. The results showed that the O-linked glycans of the CCA cell lines comprised tri- to hexa-saccharides with terminal galactose and sialic acids: NeuAc1Gal1GalNAc1, Gal2GlcNAc1GalNAc1, NeuAc2Gal1GalNAc1 NeuAc1Gal2GlcNAc1GalNAc1 and NeuAc2Gal2GlcNAc1GalNAc1 All five CCA cell lines showed a similar glycan pattern, but with differences in their quantities. NeuAc1Gal1GalNAc1 proved to be the most abundant structure in poorly differentiated adenocarcinoma (K100; 57.1%), moderately differentiated adenocarcinoma (M055; 42.6%) and squamous cell carcinoma (M139; 43.0%), while moderately to poorly differentiated adenocarcinoma (M214; 40.1%) and adenosquamous cell carcinoma (M213; 34.7%) appeared dominated by $NeuA_{c2}Gal_1GalNA_{c1}$. These results demonstrate differential expression of the O-linked glycans in the different histological types of CCA. All five CCA cell lines have abundant terminal sialic acid (NeuAc) O-linked glycans, suggesting an important role for sialic acid in cancer cells. Our structural analyses of glycans may provide important information regarding physiology of disease-related glycoproteins in CCA.