• BMB Reports
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• v.29 no.3
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• pp.248-252
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• 1996

The epidermal organ of the leech contains a complex glycoprotein molecule of mucus. The mucus excreted from annelids plays Significant role in protection against desiccation and parasites. Mucus from the Korean native leech, H. nipponia, was investigated for biochemical characteristics for possible development of biomaterials of cosmetic and pharmaceutical agents. The leech skin mucus was heavily glycosylated mucin-like protein with a high molecular weight comprised 80% carbohydrate and 20% protein. Threonine, serine, and glycine were the major components of the isolated protein and these accounted for 50% of total amino acids. The carbohydrate portion contained glucosamine, galactosamine. galactose, glucose. mannose and sialic acid in oligosaccharide form linked with threonine and serine residues of the glycoprotein.

• Microbiology and Biotechnology Letters
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• v.19 no.6
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• pp.604-609
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• 1991

Antibiotic MT-497 was purified from the culture broth of Streptomyces nigr$^1H-NMR$ and composition of amino acids, MT-497 was identified as one of the actinornycin antibiotics containing actinocin chromophore and the peptide with threonine, proline, methyl valine, sarcosine and aspartic acid.

• The Korean Journal of Zoology
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• v.3 no.2
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• pp.5-8
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• 1960

Paper partition chromatography has been applied to estimate the amino acids in the liver of Bombina orientalis Boulenger. The results obtained are as follows : 1) The presence of cystine, serine, glycine, threonine, alanine, $\beta$-alanine, tyrosine, histidine, asparagine, tryptophane, methionine, valine, phenylalanine, leucine and an unknown substance has been demonstrated in the alcoholic extracts of the material. 2) The presence of glutamine, cystine, serine , glycine, arginine, threonine, histidine, alanine, methionine, proline, valine ,phenylalanine, leucine, and two unknown substances has been demonstrated in the acid-hydrolyzed liver. 3) Tyrosine, asparagine, and trypotphane have been demonstrated only in the alcoholic extract. 4) Proline, glutamine and arginine have been demonstrated only in the acid-jydrolyzed liver.

• Archives of Pharmacal Research
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• v.17 no.1
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• pp.48-50
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• 1994

Three p-coumaroylamino acids (p-CAAs) were isolated from the yeast-elicited Ephedra distachya cultures by consecutive purification using XAD_2, silicagel and RP-HPLC. Retention times on HPLC as well as their UV, IR, NMR and MS spectral data indicated that the yeast-induced p-CAAs wre p-coumaroyl--D-valine, p-coumaroyl-D-serine and p-coumarouyl-D-threonine, respectively. The structures of p-CAAs were confirmed by the comparison of their physico-chemical properties 3with those of synthetic ones. They were isolated and identified for the first time from natural products and supposed to be accumulated as phytoalexins of Ephedra.

• Microbiology and Biotechnology Letters
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• v.22 no.6
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• pp.621-626
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• 1994

Cysteine showed strong inhibitory effect on growth and protease production of Pseudo- monas sp. RP-222 and its mutant, MR-3966. Mid- to late-log phase cells were most sensitive to the presence of 10 mM cysteine. The inhibition caused by cysteine was almost completely overcome by addition of isoleucine, leucine and valine mixture to the medium, and inclusion of iso#leucine alone could greatly reduce the inhibitory effects of cysteine. Homocysteine and #cysteine, sulfur compounds having similar structure as cysteine, inhibited to varying degrees the growth of both strains. Cysteine and homocysteine were strong inhibitors of threonine deaminase but not transa#- minase B. These results suggest a relationship between the growth-inhibitory effects of cysteine and other sulfur compounds and the inhibition of isoleucine synthesis at the level of threonine deaminase.

• Journal of Microbiology and Biotechnology
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• v.2 no.2
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• pp.122-128
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• 1992

Post-translational modifications of the nucleocapsid protein of bovine coronavirus (Quebec strain) were investigated. Coronavirions were radiolabelled in vivo with inorganic $[^{32}P]$orthophosphate and analysed by SDS-PAGE, followed by autoradiography. A single polypeptide with a migration rate of 55 KDa was identified by metabolic phosphate labelling, demonstrating that the nucleocapsid protein of bovine coronavirus was a phosphoprotein. A gene encoding the nucleocapsid protein was inserted immediately downstream from the polyhedrin promoter of Autographa californica nuclear polyhedrosis baculovirus. Spodoptera frugiperda cells infected with this recombinant baculovirus synthesized a 55 KDa polypeptide, as demonstrated by immunoprecipitation with anti-nucleocapsid monoclonal antibody. The recombinant nucleocapsid protein synthesized in Spodoptera cells could also be labelled by $[^{32}P]$orthophosphate. Phosphoamino acid analysis showed that both serine and threonine residues were phosphorylated in authentic, as well as in recombinant nucleocapsid proteins, with a relative phosphorylation ratio of 7:3. Our studies demonstrated that the nucleocapsid protein of bovine coronavirus was a serine and threonine-phosphorylated protein and that Spodoptera insect cells were able to properly phosphorylate the relevant foreign proteins.

• Molecules and Cells
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• v.26 no.1
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• pp.1-4
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• 2008

A gene's influence on an organism's Darwinian fitness ultimately determines whether it will be lost, maintained or modified by natural selection, yet biologists have few gene expression systems in which to measure whole-organism gene function. In the Department of Molecular Ecology at the Max Planck Institute for Chemical Ecology we are training "molecularly enabled field biologists" to use transformed plants silenced in the expression of environmentally regulated genes and the plant's native habitats as "laboratories." Research done in these natural laboratories will, we hope, increase our understanding of the function of genes at the level of the organism. Examples of the role of threonine deaminase and RNA-directed RNA polymerases illustrate the process.

• YAKHAK HOEJI
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• v.30 no.1
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• pp.47-50
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• 1986

The enantiomers of five amino acids (alanine, valine, threonine, leucine and phenylalanine) could be separated by gas chromatography with optically active (S)-5-isopropyll-$N^3$-phenyl-2-thiohydantoinic stationary phase, which prepared from L-valine and phenylisothiocyanate. Gas chromatographic separations on methylesterificated and N-trifluoroacetylated amino acids have been conducted in isothermal at several column temperatures (180~190, 200, $210^{\circ}C$). The separation factors were 1.29 (alanine, $190^{\circ}C$), 1.35 (valine, $190^{\circ}C$), 1.33 (threonine, $190^{\circ}C$), 1.17 (leucine, $190^{\circ}C$) and 1.05 (phenylalanine, $190^{\circ}C$) and D-isomers eluted prior to L-isomers in every instance. The result of this experiment shows that this stationary phase can be used for the separation of the other amino acids enantiomers.

• Korean Journal of Microbiology
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• v.26 no.1
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• pp.32-36
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• 1988

The yeast gene HOM3 encodes aspartokinase, which catalyses the first step (aspartate to and from beta-aspartyl phosphate) of common pathway to threonine and methionine. The yeast HOM3 gene expression is known to be regulated by threonine and methionine specific control, and also by general control of amino acid biosynthesis. Isolation and characterization of the HOM3 gene are essential for the molecular genetic study on its regulation of expression. A recombinant plasmid pSC3 (15.5kb, vector YCp50) has been cloned into E. coli HB101 from yeast genomic library through their complementing activity of HOM3 mutation in a yeast recipient strain M34-24B. Organization of the plasmid was characterized by delineation of restriction cleavage sites in the insert fragment.

• 한국생물공학회:학술대회논문집
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• 2003.04a
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• pp.79-80
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• 2003