• Korean Journal of Agricultural Science
• /
• v.18 no.1
• /
• pp.49-73
• /
• 1991

To elucidate enzymatic properties of $\alpha$-galactosidases (EC3, 2, 1, 22) from germinated soybean and Aspergillus niger changes in the enzyme activities and oligosaccharide contents during germination of soybean were determined and $\alpha$-galactosidases from germinated soybean and wheat bran culture of Aspergillus niger were purified by ammonium sulfate fractionation, ion exchange chromatography and gel filtration. Their chemical and enzymatic properties were investigated and the results obtained were summarized as follows : 1. $\alpha$-Galactosidase activity of soybean was maximized when it was germinated at $25^{\circ}C$ for 120 hours. And raffinose and stachyose in soybean were decomposed completely after 96 hours and 120 hours of germination, respectively. 2. The highest level of $\alpha$-Galactosidase activity was obtained when Aspergillus niger was grown on wheat bran medium at $30^{\circ}C$ for 96 hours. 3. Soybean $\alpha$-galactosidase was purified by 6.6 fold by ammonium slufate fractionation, ion exchange chromatography on DEAE-Cellulose and Sephadex A-50., and gel filtration on Sephadex G-150. Its specific activity was 825 units/mg protein and the yield was 2.5% of the total activity of crude extracts. 4. Aspergillus niger $\alpha$-galactosidase was purified by 23.7 fold. Its specific activity was 1,229 units/mg protein and the yield was 14% of the total activity of wheat bran culture. 5. The purified $\alpha$-galactosidases of soybean and Aspergillus niger were found to be homogeneous by polyacrylamide gel electrophoresis and by HPLC. 6. Chemical properties of the purified $\alpha$-galactosidases were : 1) The soybean $\alpha$-galactosidase was monomeric and its molecular weight was estimated to be 30,000 by SDS-PAGE whereas the Aspergillus niger $\alpha$-galactosidase was a tetrameric glycoprotein which consisted of identical subunits with molecular weight of 28,000 each.

• The Journal of Natural Sciences
• /
• v.5 no.1
• /
• pp.53-57
• /
• 1992

This experiment was carried out to elucidate some kinetic properties of the $\alpha$-galactosidase which produced and purified from Aspergillus niger ATCC 16513 and soybean(Glycine max. L). The Km value of Asp. niger and soybean $\alpha$-galactosidase were 37.0mM and 50.0mM for raffinose and55.5mM and 55.5mM for stachyose, respectively. The activity of Asp. niger and soybean $\alpha$-galactosidase were inhibited by galactose. Among the amino acids in active sites of both Asp. niger and soybean $\alpha$-galactosidase, histidine was identified by chemical modification of diethyl pyrocarbonate. Number of amino acids residues per mole of Asp. niger and soybean $\alpha$-galactosidase were 902 and 286, respectively.

• Microbiology and Biotechnology Letters
• /
• v.19 no.5
• /
• pp.477-486
• /
• 1991

To elucidate enzymatic properties of a-glactosidase (EC 3.2.1.22) from Asp. niger, a-galactosidase from wheat bran culture was purified by ammonium sulfate fractionation, ion exchange chromatography and gel filtration. And then its enzymatic propeties were investigated. The highest level of $\alpha$-galactosidase activity was obtained when Asp. niger was grown on wheat bran medium at $30^{\circ}C$ for 96 hours. The $\alpha$-galactosidase was purified by 23.7 fold by ammonium sulfate fractionation, ion exchange chromatography on DEAE-Celluose and Sephadex A-50, and gel filtration on Sephadex G-150 and its specific activity was 1,229 Unitslmg protein and the yield was 14% of the total activity of wheat bran culture. The purified $\alpha$-galactosidase was found to be homogeneous by polyacrylamide gel electrophoresis and HPLC. The $\alpha$-galactosidase was a tetrameric glycoprotein which consisted of identical subunits with molelcular weight of 28,000 each by SDS-PAGE and isoelectric point was determined analytical isoelectric focusing to be pH 4.6. The optimal temperature and pH for the $\alpha$-galactosidase activity were $40^{\circ}C$ and pH 6.5, respectively, and 54% of its activity was lost by heating at $60^{\circ}C$ for 10 mins, It was appeared to have higher affinty to raffinose than to stachyose. The K, value and activation energy of $\alpha$-galactosidase were 5.0 mM and 8.515 Kcal per mole for p-nitrophenyl- $\alpha$--D-galactopyranoside, respectively.

• Microbiology and Biotechnology Letters
• /
• v.30 no.4
• /
• pp.332-338
• /
• 2002

A strain YB-4 producing the extracellular $\alpha$-galactosidase was isolated from soil, and has been identified as Streptomyces sp. on the basis of its cultural, morphological and physiological properties. The partially purified $\alpha$-galactosidase was most active on paranitrophenyl-$\alpha$-D-galactopyranoside at pH 6.0 and 6$0^{\circ}C$. The enzyme retained 90% of its maximum activity between pH 4.0 and pH 10.0 after pre-incubation for 1 h. The enzyme was able to hydrolyze oligomeric substrates such as melibiose, raffinose and stachyose to liberate galactose residue, indicating that the $\alpha$-galactosidase of Steptomyces sp. YB-4 hydrolyzed $\alpha$-1,6 linkage.

• Food Science and Preservation
• /
• v.7 no.2
• /
• pp.201-206
• /
• 2000

${\beta}$-Galactosidase was extracted and purified from strawberry. The purified ${\beta}$-Galactosidase from strawberry was investigated their physicochemical characteristics. ${\beta}$-Galactosidase was purified 25.74 fold from strawberry. The purification procedure include ammonium sulfate fraction, acetone powder treatment and gel and ion exchange chromatography. Yield of the enzyme purification was 18.11%. The purified enzyme has native molecular weight of 116,000 dalton. Vmax value and Km value of ${\beta}$-Galactosidase were 0.077 mM ONPG/ml/15mim and 1.75x10-2mM, respectively. The optimum temperature and pH of ${\beta}$-Galactosidase were 43$^{\circ}$C and pH 4.0, respectively. The ${\beta}$-Galactosidase activity was stable below 50$^{\circ}$C and at pH 4.0 to pH 6.0. Among the metal ions Ca and Mg were did not affect, whereas K, Cu and Zn show a little effect on the enzyme activity. The ${\beta}$-Galactosidase activities were inhibited by treatment with EDTA and SDS.

• Food Science of Animal Resources
• /
• v.27 no.1
• /
• pp.110-116
• /
• 2007

Lactobacillus salivarius subsp. salivarius Nam27 with a high ${\beta}$-galactosidase activity was selected for enzymatic characterization. For purification, cell pellet was disrupted by Bead Beater, by DEAE-Sepharose and Mono-Q chromatography. The specific activity of the purified enzyme was 5,312 units/mg. The molecular weight of native monomeric ${\beta}$-galactosidase was estimated to be 30,000 dalton (monomer) by the SDS-PAGE. The optimum temperature and optimum pH were $50^{\circ}C$ and 5.0, respectively. This enzyme was stable between 35 and $55^{\circ}C$. ${\beta}$-galactosidase activity was lost rapidly above pH 7.0. But ${\beta}$-galactosidase was more stable at pH 4.0 (acidic conditions). And ${\beta}$-galactosidase activity was lost rapidly above $65^{\circ}C$ after 10 min incubation. $Ca^{2+}$ and $Zn^{2+}$ metal ions enhanced ${\beta}$-galactosidase activity by 164.09% and 127.37% while $Cu^{2+}$, $Fe^{3+}$ and $Mn^{2+}$ lowered ${\beta}$-galactosidase activity by 58.29%,85.10% and 77.66% respectively. Other metal ions didn't affect ${\beta}$-galactosidase activity significantly.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.19 no.6
• /
• pp.605-611
• /
• 1990

$\beta$-Galactosidase activity was not detected at green mature stage but were 21.79 and 380.23 units/100g-fr. wt. in mature and soft persimmon, respectively. The molecular weight of $\beta$-galactosidase was estimated to be 115, 000 daltons by the method of gel filtration. Vmax and Km value were 0.095m mo1e p-nitrophenyl-galactoside and 1.8$\times$10$^{-2}$ mM, respectively. The optimum temperature and pH of $\beta$-galactosidase were 45$^{\circ}C$ and 4.2, respectively. $\beta$-Galactosidase was inhibited by SDS.

• Microbiology and Biotechnology Letters
• /
• v.25 no.3
• /
• pp.298-304
• /
• 1997

Thermus caldophilus GK24 was selected as sources of thermostable $\beta$-galactosidase from a survey of genus Thermus. T. caldophilus GK24 (Tca) $\beta$-galactosidase was found to be inducible. The enzyme was optimally active at 75$\circ$C. Enzyme induction was achieved by addition of lactose, galactose and cellobiose to basal media. The addition of glucose to culture media had a repressive effect on further enzyme synthesis. T caldophilus GK24 was tested for production of $\beta$-galactosidase by addition of various concentration of lactose, galactose and cellobiose to standard media. Cellobiose was found to be effective for the $\beta$-galactosidase induction. The optimal induction medium for production of $\beta$-galactosidase was composed of 0.2% cellobiose, 0.3% bactotryptone, 0.3% yeast extract, basal salts and Tris/HCI(pH 7.8). The activity of the enzyme in the optimal induction medium increased nearly 16.5-fold compared to the standard medium. Tca $\beta$-galactosidase was detected when cell extracts was subjected to electrophoresis in a nondenaturing polyacryamide gel and stained for activity with 6-bromo-2-naphtyl-$\beta$-D-galactopyranoside(BNG).

• Korean Journal of Food Science and Technology
• /
• v.25 no.6
• /
• pp.694-697
• /
• 1993

Soymilk was cultured by various human large intestinal bacteria and lactic acid bacteria; Bifidobacterium longum, Lactobacillus acidophilus, Baeteroides fragilis, Eubacterium limosum, Clostridium perfringens and Escherichia coli. Among them, only B. longum utilized raffinose and stachyose actively which are major oligosaccharides present in soymilk by producing active ${\alpha}-galactosidase$ and produced greatest acid. Number of colony forming unit of B. longum reached $1.5{\times}10^{8}$ after 16 hr culture in soymilk. Also Bifidobacterium longum produced the highest level of ${\alpha}-galactosidase,\;{\beta}-galactosidase\;and\;{\alpha}-galactosidase$, in soymilk during culture.

• Microbiology and Biotechnology Letters
• /
• v.32 no.2
• /
• pp.128-134
• /
• 2004

A bacterium producing the $\alpha$-galactosidase was isolated from Korean soybean paste. The isolate YB-42 has been identified as Bacillus licheniformis on the basis on its 16S rRNA sequence, morphology and biochemical properties. The $\alpha$-galactosidase activity was detected in both the culture supernatant and the cell extract of B. licheniformis YB-42. The partially purified extracellular $\alpha$-galactosidase was obtained from the culture supernatant by DEAE-Sepharose column and Q-Sepharose column chromatography. The enzyme showed the maximum activity for hydrolysis of para-nitrophenyl-$\alpha$-D-galactopyranoside (pNP-$\alpha$Gal) at pH 6.5 and $45^{\circ}C$. It was able to hydrolyze oligomeric substrates such as melibiose, raffmose and stachyose to liberate galactose residue, indicating that the a-galactosidase of B. licheniformis YB-42 hydrolyzed $\alpha$-1,6 linkage. The hydrolyzing activity of $\alpha$-galactosidase for both pNP-$\alpha$Gal and melibiose was dramatically decreased by galactose. Both glucose and mannose inhibited the activity for pNP-$\alpha$Gal less than galactose.