• Journal of Life Science
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• v.17 no.1 s.81
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• pp.6-11
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• 2007

[ $\beta$ ]-Fructofuranosidases, a family 32 of glycoside hydrolases (GH32), share three conserved domains including the W(L/M)(C/N)DP(Q/N), FRDPK, and ECP(D/G) motifs. The functional role of the conserved acidic residues within three domains of levan fructotransferase, one of the $\beta-fructofuranosidases$, from Microbacterium sp. AL-210 was studied by site-directed mutagenesis. Each mutant was overexpressed in E. coli BL21(DE3) and purified by using Hi-Trap chelating affinity chromatography and fast performance liquid chromatography. Substitution of Asp-63 by Ala, Asp-195 by Asn, and Glu-245 by Ala and Asp decreased the enzyme activity by approximately 100-fold compared to the wild-type enzyme. This result indicates that three acidic residues Asp-63, Asp-195, and Glu-245 play a major role in catalysis. Since the three acidic residues are present in a conserved position in inulinase, levanase, levanfructotransferase, and invertase, they are likely to have a common functional role as nucleophile, transition state stabilizer, and general acid in $\beta-fructofuranosidases$.

• The Korean Journal of Food And Nutrition
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• v.36 no.6
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• pp.526-534
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• 2023

To improve usability of super sweet corn, extracts were prepared with hydrolytic enzyme and changes in physicochemical and antioxidant properties were analyzed. Soluble solids and reducing sugars contents were higher in all enzyme treatment groups than in the control. When enzyme treatment time increased, contents of soluble solids and reducing sugars were also increased. There was no significant difference in lightness between treatment groups, with redness showing the highest value in the control and yellowness showing the highest value in the invertase treatment group. Free sugar content in the control was the lowest. However free sugar content in the enzyme combination treatment group was increased by more than four times compared to that in the control. Contents of ascorbic acid, flavonoids and polyphenols were higher in the enzyme treatment group than in the control. In particular, the enzyme combination treatment group showed the highest content. DPPH and ABTS radical scavenging abilities were significantly higher in all enzyme treatment groups than in the control. Radical scavenging abilities of cellulase treatment group and enzyme combination treatment group showed high activity. The activity increased when enzyme treatment time increased. The combined enzyme treatment method for super sweet corn was suitable for food processing.

• Korean journal of applied entomology
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• v.16 no.4 s.33
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• pp.199-208
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• 1977

Activities of various hydrolytic enzymes produced by three plant pathogenic fungi, Sclerotium rolfsii Sacc., Sclerotinia sclerotiorum (Lieb.) deBary and Helminthosporium sigmoideum var. irregulare Crallery et Tullius, were measured. Activties and amounts of the enzymes in mycelia, cultural filtrates, and sclerotia(except of sclerotia of H. sigmoideum var. irregulare) were estimated at various pH levels in order to find out optimal pH for their enzymatic activities. Enzymes such as cellulase (ex), invertase, xylanase, $\beta-amylase$, polymethylgalacturonase, polygalacturonase, phosphatase and protease were estimated. Culture solution for production of enzymes was prepared by adding of 10g, D-glucose, 1.3g $NH_4NO_3,\; 0.5g\; MgSO_4,\;7H_2O,\; and\; 1.0g\; KH_2PO_4$ into 1 liter of potato decoction plus 2ml of micro element solution consisting of 0.2mg. Fe, 0.2mg Zn, and 0.1mg Mn as the sulphates into 1 liter of distilled water. All tested mycelia and cultural filtrates were obtained from the cultures incubarted in previous solution for ten days at $25^{\circ}C$, and sclerotia were harvested from PDA plates of 3. days old, The crude enzyme solutions were prepared according to the method of Miyazaki etal. Ten days after incubation, activities of Cx produced by Scl. sclerotiorum were higher than those of the other fung and each of Cx from three fungi showed different pH optima, such as S. rolfsii and Scl. schlerotiorum in acid side (around pH 3.0), H. sigmoideum var. irregulare in neutral side (around pH 6.3). Invertase activities of S. rolfsii were 20 times higher than those of the other fungi in all samples. All tested fungi, however, showed no significant difference between the enzymatic activities of their cultural filtrate and mycelia and the activities in sclerotia of S. rolfsii and Scl. sclerotiorum were hardly recognized. There were multiple peaks on the xylanase activity curves of three fungi in terms of pH values. High activities of the xylanase were revealed in sclerotia of S. rolfsii and Scl. sclerotiorum, and in mycelia of H. sigmoideum var. irregulare. The highest activities of $\beta-amylase$ were shown both in mycelia and cultural filtrate of H. sigmoideum var. irregulae among the tested fungi, and their optimal pH was 6.2 in both mycelia and cultural filtrate. In the S. rofsii and Sel. sclerotiorum, however, the activities of cultural filtrates were higher than those of the other fungi, and optimal pH was 3.0 and 6.2 for cultural filtrate and both mycelia and sclerotia, respectively. Activities of PMG were high in cultural filtrates of all tested fungi, especially in Scl. sclerotiorum and H. sigmoideum var. irregulare. Mycelia of themalso showed the considerable activities. Optimal pH for enzymatic activities were variable with thekind of fungi or with the samples measured. The highest activities of PG were presented by mycelia of S. rolfsii and Scl. sclerotiorum. $9.l\mu /min.\; and\; 9.5\mu g/min.$, respectively. Optimal pH for activity of PG in mycelia was around 4.5 in S. rolfsii and around 3.0 in Scl. sclerotiorum. Phosphatase of S. rolfsii and Scl. sclerotiorum was more active in acid side (optimal PH3. 5) and that of H. sigmoideum var. irregulare showed one peak each in acid, neutral and alkaline side. But the highest peak was at pH 9.5. Protease of all tested fungi was more active at pH 10.0, especially that of the cultural filtrate of H. sigmoideum var. irregualre.

• Journal of Microbiology
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• v.35 no.2
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• pp.141-148
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• 1997

Alcaligenes xylosoxydans strain SMN3 capable of utilizing biphenyl grew not only on phenol, and benzoate, but also on salicylate. Catabolisms of biphenyl and salicylate appear to be interrelated since benzoate is a common metabolic intermediate of these compounds. Enzyme levels in the excatechol 2. 3-dioxygenas which is meta-cleavage enzyme of catechol, but did not induce catechol 1, 2-dioxygenase. All the oxidative enzymes of biphenyl and 2, 3,-dihydroxybiphenyl (23DHBP) were induced when the cells were grown on biphenyl and salicylate, respectively. Biphenyl and salicylate could be a good inducer in the oxidation of biphenyl and 2, 3-dihydroxybiphenyl. The two enzymes for the degradation of biphenyl and salicylate were induced after growth on either biphenyl or salicylate, suggesting the presence of a common regulatory element. However, benzoate could not induce the enzymes responsible for the oxidation of these compounds. Biphenyl and salicylate were good inducers for indigo formation due to the activity of biphenyl dioxygenase. These results suggested that indole oxidation is a property of bacterial dioxygenase that form cis-dihydrodiols from aromatic hydrocarbon including biphenyl.

• Journal of Microbiology and Biotechnology
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• v.15 no.1
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• pp.99-104
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• 2005

Microbacterium laevaniformans levansucrase synthesized various hetero-oligosaccharides by transferring fructosyl residue from sucrose to various saccharides as acceptors. The acceptor specificity test showed that reducing saccharides were more favorable acceptors than nonreducing saccharides. The transfructosylated product, fructosyl galactose, was produced in the presence of D-galactose as an acceptor. The chemical structure of the resulting fructosyl galactose was analyzed by yeast invertase and NMR, and identified as O-$\alpha$-D-galactosyl-(1${\to}$2)-$\beta$-D-fructofuranoside. These results indicate that the main transfructosylation activity of the enzyme is to make nonreducing transferred products via a transfer of fructosyl residue to acceptor molecules having reducing group. When nonreducing sugars, such as methyl $\alpha$-D-glucoside and methyl $\alpha$-D-galactoside, were used as an acceptor, the transfer product was also formed in spite of the reducing group blocked with methyl group. The fact that no transfer product was formed with sugar alcohols as acceptors was suggested to be due to marked conformational difference of acceptors.

• Journal of Applied Biological Chemistry
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• v.42 no.2
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• pp.71-74
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• 1999

The crude enzyme prepared from the culture supernantant of Arthrobacter sp. S37 was purified by Phenyl Toyopearl column chromatography. Six endo-inulinases were detected by activity staining on native PAGE and named Inu I to Inu VI. Endo-inulinase were further purified by DEAE cellulose column chromatography and band slicing. Inu II~VI produced mainly inulotriose (F3) and inulotetraose (F4) as well as a small amount of inulobiose (F2) and fructose in contrast to Inu I producing F3, F4 and F5 from inulin. The N-terminal amino acid sequence of native and six CNBr-cleaved fragment of Inu VI were determined. No homology was found in amino acid sequences between Inu VI and other fructan hydrolase including invertase reported.

• Korean Journal of Medicinal Crop Science
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• v.13 no.6
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• pp.293-299
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• 2005

To determine optimal fermentation period of vegetables mixed with black sugar without innoculation of microorganisms, changes in chemical components, quality characteristics of the fermented broth and physiological functionality during the fermentation period were investigated, pH and $^{\circ}BX$ of the fermented broths were decreased gradually during the fermentation period. Except for radish, L and a color values of fermented broths were increased but b values were decreased during fermentation period. Viscosity of fermented broths of vegetables were decreased after 3 months of fermentation. ${\alpha}-Amylase$ activity in fermentation broth of brocolli, eggplant, cabbage, chicory, aralia, radish were increased to 460, 430, 180, 420, 560, 260 after six months fermentation period. In radish and tomato fermentation broth, invertase activity were increased to 200 and 460 units and cellulase activity were increased to 280 and 140 after six months fermentation period. The content of total phenolic compounds and electron donating ability were the highest after 2 to 4 months fermentation period and decreased thereafter. No significant level of tyrosinase inhibitory activity and SOD-like activity were observed. In the sensory evaluation test of aralia fermentation broth of droop, sweet and sour flavor and bitter, astringent taste were decreased during the fermentation period and droop tastes were highest in 3 months. In radish fermentation broth, radish flavor and pungent taste were decreased and sweet taste was increased during fermentation period. Acceptability in overall was the greatest after three months. Based on the results stated above, optimal fermentation period was appropriated 3 or 4 months.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.5
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• pp.746-751
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• 2015

The quality characteristics of Oenothera biennis juice (OJ) fermented with various concentrations of sugar solutions (50, 60, and $70^{\circ}Brix$) and at different temperatures (20 and $30^{\circ}C$) were investigated. The sugar concentration and pH of fermented OJ decreased during fermentation and more rapidly decreased at $30^{\circ}C$ rather than at $20^{\circ}C$. The number of total bacteria increased during 6 days of fermentation and decreased gradually thereafter, and coliform bacteria were not detected after 8 to 10 days of fermentation at 20 and $30^{\circ}C$. Enzyme activities (invertase, amylase, and cellulase) of fermented OJ with $50^{\circ}Brix$ sugar solution were the highest among the different treatments after fermentation for 4 days at $30^{\circ}C$. Total polyphenol content and DPPH radical scavenging ability increased during fermentation. The highest total polyphenol contents and DPPH radical scavenging ability were 7.1 mg TAE/mL and 58.6%, respectively, when fermented at $30^{\circ}C$ with $50^{\circ}Brix$ sugar solution.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.25 no.4
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• pp.43-58
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• 1980

The study was intended to know the responses of the nitrogen application levels (3, 6, 9, 12 and 15kg ai per $1O^a$) to grain yield and quality of two-malting barley, Golden melon and Hyang maek in 1980. There was investigated chlorophyll content, dry weight, heading, grain yield, yield components, contents of protein, fat and carbohydrate and activity of $\beta$-amylase and invertase. Nitrogen increment was effective to increase of number of grains per spike and number of spikes per unit area, increase of protein content and decrease of $\beta$-amylase activity, but it was not recognized the yield increase under the 12% protein content.

• KSBB Journal
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• v.10 no.4
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• pp.374-385
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• 1995

Nutritional requirements and cultural conditions for the production of extracellular gelatin-degrading proteolytic enzyme by Bacillus subtilis B0021 were investigated. Optimum carbon source for proteolytic enzyme production was salicin, but it was substituted by glucose for economical reason. The fermentation medium giving a maximum proteolytic enzyme activity was consisted of 1.5%(w/v) glucose, 2.5%(w/v) yeast extract, and 0.001%(w/v) manganese sulfate and 0.002%(w/v) ferrous sulfate. Proteolytic enzyme activity of B. subtilis B0021 was completely inhibited by 0.5%(w/v) tannic acid. Initial pH was optimal at 7.0 and the enzyme activity in the flask culture usually reached a maximal level after 36 hours of fermentation at $30^{\circ}C$. In the $5\ell$ fermentor fermentation at $30^{\circ}C$, enzyme activity was maximum at 36 hour of cultivation but after this enzyme activity was decreased rapidly. Initial viscosity of 45%(w/v) gelatin(2,800mPas) was decreased rapidly to 96%(mPas) after hydrolysis for 4hr at $40^{\circ}C$ by crude enzyme of B. subtilis B0021.