• Journal of the Korean Society of Food Science and Nutrition
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• v.19 no.5
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• pp.434-442
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• 1990

Aspergillus sp. CC-29 ws selected for its strong protease activity among various stains of molds found in soil. It was found that the production of alkaline protease reached to maximum when the wheat bran medium containing glucose as carbon source had been cultured for 4 days. Alkaline proteased was purified 36.10 fold from Aspergillus sp. CC-29 The purification procedures included ammonium sulfate fractunation gel filteration on Sepha-dex G-75 G-150 and DEAE-cellulose ion-exchange chromatography, The yield of the purified enzyme was 22.40% The purified enzyme was confirmed as a single band by the polyacryla-mide. When the purified enzyme was applied to SDS-PAGE the molecular weight was estima-ted 24000. The optimum pH for the enzyme activity was 9.0 and the optimum temperature was 4$0^{\circ}C$ The reaction of this enzyme followed typical Michaelis-Menten kinetics with the Km value of 2.10$\times$10-4M with the Vmax of 29.41 $\mu$g/min. The enzyme was reactively stable in alkalic condition and unstable by heat treatment. The activity of alkaline protease was increased by the addition of Ca2+ whereas it was inhibited by Hg2+ Zn2+ at concentration of 1$\times$10-3M.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.32 no.4
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• pp.66-73
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• 2000

Alkaline sulfite-anthraquinone(AS-AQ) cooking process has been applied to unground pine bark. The properties of the spent liquor such as molecular weight distributions, sulfonic equivalent weights, degree of sulfonation, phenolic hydroxyl groups and kaolin dispersing ability have been investigated to evaluate the possibility of using this liquor as concrete additives or binders. In the case of ground bark meal, more than 90% delignification was achieved at the optimal cooking conditions. However, applying these conditions on unground bark the delignification was slightly retarded. The decrease in the degree of delignification may be attributed to less penetration and diffusion of chemicals during the cooking of the bark. Increasing the cooking temperature only by $5^{\circ}C$ improved the delignification of the bark and about 90% delignification can be achieved. These results indicate that bark can be used successfully during AS-AQ cooking without any mechanical or physical pretreatment. The properties of lignin or polyphenol sulfonates in the spent liquor after AS-AQ cooking of the bark were compared with Sunflo-R, which is commercial lignosulfonate(CLS) prepared from wood. The weight average molecular weights(Mws) estimated by gel-filteration chromatography was found to be ranging from 1,200~1,800. These are considerably lower than those in CLS. Lignin or polyphenol sulfonates in the spent liquor of bark and CLS have similar degree of sulfonation, but the phenolic hydroxyl group was 1.8 times higher than CLS. Moreover, the dispersing abilities of the spent liquors were better than that of CLS, especially after 0.1% addition to kaolin suspension.

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.10
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• pp.1447-1452
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• 2011

Polyphenol oxidase (PPO) isoforms were partially purified from oyster mushroom (Pleurotus ostreatus) using various chromatography techniques, and their characteristics of heat stability, substrate affinity, optimum pH, and optimum temperature were investigated. Three PPO isoforms named PO-I, PO-II-1, and PO-II-2 were partially purified from oyster mushroom. The molecular weight of PO-II-1 was 70 kDa and PO-I and PO-II-2 were less than 6 kDa each. Characterization was carried out using a PPO isoform partially purified by hydrophobic interaction chromatography. Optimum temperature was $55^{\circ}C$ and optimum pH 5.0. However, the PPO was inactivated at neutral pH or by heating at $80^{\circ}C$ for 30 min, while the 40% PPO still remained active after heating at $60^{\circ}C$ for 45 min. The PPO isoform showed the highest substrate affinity to chlorogenic acid and pyrogallol, in which KM values were 1.01 and 2.06 mM, respectively. Therefore, these results suggested that the mushrooms should be stored at a pH higher than 7.0 and at a low temperature to prevent enzymatic browning.

• Korean Journal of Food Science and Technology
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• v.18 no.2
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• pp.158-162
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• 1986

Various cell wall polysaccharides such as ionically associated pectin (IAP), covalently bounded pectin (CBP),4N potassium hydroxide soluble hemicellulosic fraction (HF,) and 0-3N soluble hemicellulosic fraction (HF,) were fractionated from crude cell wall of the fresh and soft persimmon by chemical method. The changesin cell wall polysaccharides were studied by gel filteration chromatography . The content of crude cell wall remarkably decreased in the soft persimmon. The decreasing rates of IAP, CBP and $HF_2$ were 59, 60 and 74%, respectively, while $HF_1$ and cellulose changed only a little during softening. Sugar compositions of IAP and CBP were 72-84% uronic acid, 5-1% hexose and 11-16% pentose, and also the hemicellulose was composed of uronic acid besides hexose and pentose that was hemicellulosic components. The loss rate of pentose in IAP, of hexose in CBP, of hexose and uronic acid in $HF_2$, of pentose in $HF_1$ increased during softening. Though apparent average molecular freight of all polysaccharides shifted from high molecular freight to low molecular weight polymer, the shifting degree of CBP and $HF_2$ was especially remarkable during softening. It is suggested that the severe softening phenomenon of persimmon involved the degradation and dissolution of wall bound-CBP and $HF_2$ which were associated with each other.

• Applied Biological Chemistry
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• v.39 no.6
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• pp.494-500
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• 1996

Uptake of hen metal ions by water dropwort (Oenanthe stolonifera DC.) and its cadmium-binding protein were studied to probe for good method to remove heavy metal contaminants from environments. The plant was cultured in the culture medium (pH 7.0) containing the various concentrations of $Cd^{2+}$, $Cr^{3+}$ or $Pb^{2+}$, for 3 and 7 days. The residual heavy metals deposited in roots linearly increased as the metal ions concentration increased up to 17 ppm for $Cd^{2+}$, 20 ppm for $Cr^{3+}$ and 50 ppm for $Pb^{2+}$. Above these concentrations, the plant growth was inhibited and the uptake rates of the metal ions decreased. The heavy metals absorbed by the plant were mostly deposited in roots. In particular, the residual concentration of lead in roots was about four times higher than those of cadmium and chromium. When cultured in the medium containing 20 ppm of each metal ion, 80% of cadmium, 90% of cromium and 96% of lead were deposited in roots out of the total residual metal ions in the plant. These values correspond to 6.1 mg of cadmium, 5.2 mg of chromium and 23.6 mg of lead per one gram of roots tissue on a dry weight basis. A cadmium-binding protein was partially purified by extraction, gel filtration and DEAE-Cellulose chromatography from water dropworts that was grown in the medium containing 20 ppm $Cd^{2+}$. The purified protein was a single band on SDS- and non-denaturing- polyacrylamide gel electrophoresis. Its molecular mass was estimated to be ca. 5,000 dalton by gel filteration. Analysis of amino acid composition of the protein indicated that it had a typical amino acid composition of heavy metal-binding protein in that it contained 27% of acidic amino acids and 9.9% of cysteine. However, it is likely that the protein is a new plant metal-binding protein, since its amino acid composition is somewhat different from those of phytochelatins that have been known so far.