• 한국생물공학회:학술대회논문집
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• 2000.11a
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• pp.495-499
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• 2000

The relative affinity of seaweed alginate, polyguluronate and polymannuronate for cations was investigated. The cations used in this study were $Ca^{2+}$, $Cd^{2+}$, $Co^{2+}$, $Cu^{2+}$, $Fe^{3+}$, $Hg^{2+}$, $Mg^{2+}$, $Mn^{2+}$, $Pb^{2+}$, $Rb^{1+}$, $Sr^{2+}$ and $Zn^{2+}$. The ability of cations to precipitated polymers was determined as the relative affinity of seaweed alginate, polyguluronate and polymannuronate for cations. The relative affinity of polymers for cations in order are as follow: Seaweed alginate: $Fe^{3+}$,$Cu^{2+}$,$Cd^{2+}>Pb^{2+}>Co^{2+}$,$Zn^{2+}>Ca^{2+}>Sr^{2+}$,$Rb^{1+}>Mn^{2+}>Mg^{2+}$,$Hg^{2+}$ Ployguluronate:$Fe^{3+}$,$Cu^{2+}$,$Cd^{2+}>Ca^{2+}$,$Co^{2+}$,$Pb^{2+}>Sr^{2+}$,$Rb^{1+}$,$Zn^{2+}>Hg^{2+}$,$Mn^{2+}>Mg^{2+}$ Polymannuronate:$Fe^{3+}$,$Cd^{2+}$,$Cu^{2+}>Ca^{2+}$,$Pb^{2+}>Zn^{2+}$,$Rb^{1+}$$Sr^{2+}$,$Hg^{2+}>Co^{2+}>Mn^{2+}>Mg^{2+}$

• Journal of Life Science
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• v.22 no.1
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• pp.7-15
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• 2012

A polyguluronate-specific lyase from Streptomyces sp. strain M3 has been previously cloned and characterized. In this study, the M3 alginate lyase gene in the pColdI vector was mutated by site-directed mutagenesis and random mutagenesis to enhance the alginate degrading activity. Six mutants were obtained: Ser25Arg, Phe99Leu, Asp142Asn, Val163Ala, Lys191Glu, and Gly194Cys. Phe99Leu and Lys191Glu mutants completely lost their alginate lyase activity, whereas the alginate degrading activity of Gly194Cys mutant increased by nearly 10 fold. The 3-D protein structure of M3 alginate lyase, which was constructed using the Swiss-Model automodeler, was also compared to the crystal structure of another alginate lyase. A mutated glycine residue was positioned between Gly193 and Tyr195 of the C-terminal conserved sequence, YFKAGXYXQ. A phenylalanine residue (at position 99) and a glycine residue (at position 194) mutated in this study were distant from the active site, but the degrading activity was strongly affected by their mutation.

• Journal of Life Science
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• v.19 no.5
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• pp.553-560
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• 2009

Based on $P_{1/2}$ values, relative affinities of alginate, polyguluronate, and polymannuronate for metal ions are, in order, as follows; 1) seaweed alginate: $Cu^{2+}$ > $Cd^{2+}$ > $Pb^{2+}$ > $Fe^{3+}$ >> $Zn^{2+}$ > $Sr^{2+}$ > $Ca^{2+}$ > $Co^{2+}$ >> $Cr^{6+}$ > $Mn^{2+}$ >> $Hg^{2+}$, $Mg^{2+}$, $Rb^+$, 2) polyguluronate: $Cd^{2+}$ > $Cu^{2+}$ > $Pb^{2+}$ > $Fe^{3+}$ >> $Ca^{2+}$ > $Sr^{2+}$, $Zn^{2+}$, $Co^{2+}$ >> $Mn^{2+}$ > $Cr^{6+}$ >> $Hg^{2+}$, $Mg^{2+}$, $Rb^+$, and 3) polymannuronate: $Cd^{2+}$, $Cu^{2+}$ > $Fe^{3+}$ > $Pb^{2+}$ > $Ca^{2+}$ > $Zn^{2+}$ > $Sr^{2+}$ > $Co^{2+}$ > $Cr^{6+}$ >> $Mn^{2+}$ >> $Hg^{2+}$, $Mg^{2+}$, $Rb^+$. Amounts of the metal ions, $Cd^{2+}$, $Cu^{2+}$, $Fe^{3+}$, $Pb^{2+}$, and $Zn^{2+}$, bound to 1 g of seaweed alginate, were measured as $363.5{\pm}45.0$, $226.3{\pm}9.2$, $1,299.4{\pm}$81.3, 500.7${\pm}$27.7, and 165.9${\pm}$11.4 mg, respectively. Amounts of the metal ions, $Cd^{2+}$, $Cu^{2+}$, $Fe^{3+}$, $Pb^{2+}$, and $Zn^{2+}$, bound to 1g of polyguluronate, were 354.5${\pm}$26.5, 177.6${\pm}$8.7, 1,288.6${\pm}$60.1, 424.0${\pm}$7.4, and 140.2${\pm}$28.5 mg, respectively, whereas those bound to 1 g of polymannuronate were 329.0${\pm}$10.3, 206.9${\pm}$1.9, 1,635.6${\pm}$11.1, 419.8${\pm}$12.6, and 251.0${\pm}$49.1 mg, respectively. Due to its higher solubility than alginate and higher affinity for metal ions than polyguluronate, polymannuronate can be used for bioremediation or biosorption of toxic and/or noble metal ions.

• YAKHAK HOEJI
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• v.46 no.4
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• pp.283-289
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• 2002

The cholesterol and fatty acid levels in serum and liver were compared in 4-week-old Sprague-Dawley male fed by addition of polymannuronate (M, 5.0％), polyguluronate (G, 5.0％), and polymannuronate and polyguluronate (MG, 2.5％ to each) with by addition of cholesterol (1.0％). Feed efficiency by the addition of M, MG, and G was lower than cholesterol fed group (p＜0.01). The liver weights were less in M, MG, and G fed groups than in cholesterol fed group (p＜0.01). Triglyceride levels in serum and liver were 58.2∼77.4％ and 51.5∼65.5％ lower in M, G and MG fed groups than cholesterol fed group, respectively. Total-, LDL-, and free-cholesterol levels in serum and liver in M, MG, and G fed group were significantly lower than cholesterol fed group. The cholesterol levels were the most reduced in M fed group. However, HDL- cholesterol level in serum was increased in M, MG, and G fed group (p＜0.01). The of polyene levels were 47％ higher in serum and 76％ in liver in M fed group than in cholesterol fed group. The activities of GOT and GPT were lower in M, MG, and G fed group than in cholesterol fed group (p＜0.01). Above the results demonstrate that supplementation of low molecular polymannuronate in diets improve physiologically lipid composition in serum and liver.

• Journal of Life Science
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• v.19 no.1
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• pp.34-39
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• 2009

Alginate with a MW of 1,283 kDa was hydrolyzed with 0.4 M organic acids at $100^{\circ}C$ for 3 hr. Molecular weights of alginates hydrolyzed with organic acids ranged from 7.5 to 53.2 kDa. There was no significant difference in the molar ratio of mannuronate to guluronate in alginates hydrolyzed with organic acids. Acetic add was found to be the most effective organic acid for hydrolysis of alginate. The MW of alginate decreased with increasing concentration and reaction time with acetic acid as a hydrolyzing agent. The correlations between the MW of hydrolyzed alginate and concentration of acetic acid as well as reaction time with 0.4 M acetic acid were plotted and the relevant equations obtained in this study. Polymannuronate and polyguluronate were isolated by pH adjustment of alginate hydrolyzed with 0.4 M acetic add. The molar percentages of mannuronate in polymannuronates isolated from alginate hydrolyzed with 0.4 M acetic acid at $100^{\circ}C$ were increasing in proportional to the reaction time such as 75% for 1 hr, 90% for 3 hr, and 98% for 5 hr of reaction time.

• Proceedings of the Korean Society of Life Science Conference
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• 2001.02a
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• pp.59-59
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• 2001

• Journal of Life Science
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• v.19 no.11
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• pp.1522-1528
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• 2009

A marine bacterium was isolated from brown seaweeds for its ability to degrade alginate. Analysis of 16S ribosomal DNA sequence revealed that the strain belongs to Streptomyces like strain ALG-5 which was reported previously. New alginate lyase gene of Streptomyces sp. M3 was cloned by using PCR with the specific primers designed from homologous nucleotide sequences. The consensus sequences of N-terminal YXRSELREM and C-terminal YFKAGXYXQ were conserved in the M3 alginate lyase amino acid sequences. The homology model for the M3 alginate lyase showed a characteristic structure of $\beta$-jelly roll fold main domain like alyPG from Corynebacterium sp. ALY-1. The homogenate of the recombinant E. coli with the alginate lyase gene showed more degrading activity for polyguluronate block than polymannuronate block. The results from the multiple alignments and the homology modeling elucidated in the M3 alginate lyase can be classified into family PL-7.