• Title, Summary, Keyword: $\beta$-galactosidase

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Characteristics and Activity Changes of $\beta$-Galactosidase during Maturation and Postharvest of Persimmon Fruits (감과실의 성숙과 추숙중의 $\beta$-Galactosidase활성 변화 및 특성)

  • 신승렬;하유덕;김진구;김순동;김광수
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.19 no.6
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    • pp.605-611
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    • 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.

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Purification and Characteristics of ${\beta}$-Galactosidase from Strawberry (딸기 ${\beta}$-Galactosidase의 정제 및 생화학적 특성)

  • Lee, Kwang-Hee;Yoon, Kyung-Young;Kim, Kwang-Soo;Kim, Nam-Woo;Shin, Seung-Ryeul
    • Korean Journal of Food Preservation
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    • v.7 no.2
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    • pp.201-206
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    • 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.

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Studies On Induction of ${\beta}$-D-galactosidase In Candida kefyr (Candida kefyr의 ${\beta}$-D-galactosidase 合成誘導에 關한 硏究[I])

  • Chun, Soon-Bai
    • Korean Journal of Microbiology
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    • v.22 no.2
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    • pp.77-84
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    • 1984
  • This examined some conditions for the induction of ${\beta}$-D-galactosidase synthesis in Candida kefyr CBS 834. The optimal pH, temperature, and inoculum size either for growth or${\beta}$-D-galactosidase synthesis were 5.5, $30^{\circ}C$ and above 0.2 at A610nm, respectively. Enzyme activity began to increase at 2h after the addition of inducer, and continued to increase linearly up to $2{\sim}3h$ before reaching stationary phase, and thereafter its activity was decreased. ${\beta}$-D-galactosidase was induced either by lactose or galactose but not either by glucose or ethanol. The greater activity of ${\beta}$-D-galactosidase on galactose than on lactose indicated that the former might be natural inducer for ${\beta}$-D-galactosidase synthesis. The rate of its induction as a function of lactose concentration showed that enzyme activity increased linearly above 4mM, while it was very low below that. Glucose represed the induction of ${\beta}$-D-galactosidase, and the period of adaptation to inducer from other carbon sources was relatively short.

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Properties of β-Galactosidase from Lactobacillus salivarius subsp. salivarius Nam27

  • Bae, Hyoung-Churl;Renchinkhand, Gereltuya;Nam, Myoung-Soo
    • Food Science of Animal Resources
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    • v.27 no.1
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    • pp.110-116
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    • 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.

Production and Characterization of ${\beta}$-galactosidase from Bacillus licheniformis Isolated from Doenjang (된장에서 분리된 Bacillus licheniformis의 ${\beta}$-galactosidase 생산성과 효소특성)

  • Jin, Hyun Kyung;Yoon, Ki-Hong
    • Microbiology and Biotechnology Letters
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    • v.42 no.4
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    • pp.339-346
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    • 2014
  • A bacterial strain was isolated from homemade doenjang (Korean fermented soybean paste) as a producer of the extracellular ${\beta}$-galactosidase, capable of hydrolyzing lactose to liberate galactose and glucose residues. The isolate YB-1414 has been identified as Bacillus licheniformis on the basis of its 16S rDNA sequence, morphology and biochemical properties. The production of ${\beta}$-galactosidase by B. licheniformis YB-1414 reached maximum levels of 6.2 U/ml in culture medium containing wheat bran (1%) and yeast extract (2.5%) as carbon and nitrogen sources, respectively. Particularly, the insoluble fraction was more effective for ${\beta}$-galactosidase production than the soluble extract of wheat bran. The enzyme exhibited maximum activity for hydrolysis of para-nitrophenyl-${\beta}$-D-galactopyranoside (pNP-${\beta}Gal$) under reaction conditions of pH 6.0 and $55-60^{\circ}C$. Its hydrolyzing activity for pNP-${\beta}Gal$ was drastically decreased by the addition of low concentrations of galactose, but only slightly decreased by glucose, with 85% of maximal activity in the presence of 400 mM glucose.

Characterization of the \beta-Galactosidase Produced by Streptomyces sp. YB-10 (\beta-Galactosidase를 생산하는 Streptomyces sp. YB-10의 분리 및 효소 특성)

  • 윤기홍;이경섭;김창진
    • Microbiology and Biotechnology Letters
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    • v.31 no.2
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    • pp.151-156
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    • 2003
  • A strain YB-10 was isolated from soil as a producer of the extracellular $\beta$-D-galactosidase, which catalyzes the hydrolysis of lactose. The strain YB-10 was identified as Streptomyces sp. on the basis of its cultural, morphological and physiological properties. After treating culture supernatant of the isolate with ammonium sulfate, the precipitated protein was used as a crude $\beta$-galactosidase for analyzing its reaction properties with para-nitrophenyl-$\beta$-D-galactosidase(pNP-$\beta$Gal) as a substrate. The $\beta$-galactosidase showed its maximal activity at pH 6.0 and 6$0^{\circ}C$. The enzyme was also active on lactose. The hydrolyzing activity of $\beta$-galactosldase for pNP-$\beta$Gal and lactose was decreased by galactose. Its hydrolyzing activity far lactose was also decreased by glucose, but the activity for pNP-$\beta$Gal was increased to 1.8-folds by glucose.

Production of Galactooligosaccharides using Immobilized $\beta$-Galactosidase (고정화 $\beta$-Galactorsidase에 의한 갈락토올리고당의 생산)

  • 김창렬
    • The Korean Journal of Food And Nutrition
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    • v.12 no.1
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    • pp.63-68
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    • 1999
  • Production of galactooligosaccharides by an immobilized $\beta$-galactosidase from Aspergillus niger CAD 1 in sodium alginate was investigated. The ranges of temperature and pH for the maximum stability of im-mobilized $\beta$-galactosidase were 20~45$^{\circ}C$ and 4.0~5.5, respectively. The activation energy for the immob-illized $\beta$-galactosidase was 13,400 cal/mole At the concentration of the immobilized $\beta$-galactosidase 0.12 unit/g in sodium alginate the yield of galactooligosaccharides in cheese whey containing 20% lactose was 18% after incubation for 72 hr at 45$^{\circ}C$. The remaining activity for the immobilized $\beta$-galactosidase 10 times repeated use 87%.

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Lactase activity in yoghurt and lactic acid bacteria (요구르트와 유산균에서의 Lactase Activity)

  • Lee, Kwang-Hee
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.21 no.1
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    • pp.60-63
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    • 1992
  • Individual starter culture were inoculated into liquid medium and incubated at $40^{\circ}C$ for 16 hours. Whole cell were obtained and evaluated for ${\beta}-galactosidase$ activity using orthonitrophenyl-${\beta}-D-galactopyranoside$ (ONPG) as substrate. S. thermophilus had more ${\beta}-galactosidase$ activity than other Lactobacilli did. To study the effect of storage temprature on enzyme activity of yoghurt, some samples of cultured yoghurt were stored under refrigeration $(4^{\circ}C)$, and the others under room temperature $(23^{\circ}C)$. At $4^{\circ}C$, yoghurt had ${\beta}-galactosidase$ activity and many viable bacteria in 1 month. After 20 days, yoghurt had maximum ${\beta}-galactosidase$ activity. At $23^{\circ}C$, yoghurt had ${\beta}-galactosidase$ activity by 5 days. As this experiment shown ${\beta}-galactosidase$ activity was ascribed to viable bacteria, especially S. thermophillus. Commercial yoghurt had lower ${\beta}-galactosidase$ activity. There were considerable variations with regard to the lactose hydrolyzing capabilities of commercial yoghurt samples.

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Molecular Cloning and Characterization of the ${\beta}-Galactosidase$ Gene from Bifidobacterium adolescentis Int57

  • Park, Myeong-Soo;Yoon, Hyeon-Jin;Rhim, Seong-Lyul;Ji, Geun-Eog
    • Journal of Microbiology and Biotechnology
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    • v.11 no.1
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    • pp.106-111
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    • 2001
  • A ${\beta}-galactosidase$ gene of Bifidobacterium adolescentis Int57 (INT57) was cloned using the shotgun method. The sequence of the ${\beta}-galactosidase$ gene existing in the sequenced 3,260-bp fragment showed higher than 40% homology with other bacterial ${\beta}-galactosidase$ genes. The expression in Escherichia coli suggested that the ${\beta}-galactosidase$ might have a monomeric, dimeric, or tetrameric protein structure. This is probably the first peer-reviewed sequence analysis of the ${\beta}-galactosidase$ gene of the genus Bifidobacterium.

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Improving Soluble Expression of β-Galactosidase in Escherichia coli by Fusion with Thioredoxin

  • Nam, E.S.;Jung, H.J.;Ahn, J.K.
    • Asian-Australasian Journal of Animal Sciences
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    • v.17 no.12
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    • pp.1751-1757
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    • 2004
  • Recombinant heterologous proteins can be produced as insoluble aggregates partially or perfectly inactive in Escherichia coli. One of the strateges to improve the solubility of recombinant proteins is fusion with a partner that is excellent in producing soluble fusion proteins. To improve the production of soluble $\beta$-galactosidase, the gene of Thermus thermophilus KNOUC112 $\beta$-galactosidase (KNOUC112 $\beta$-gal) was fused with thioredoxin gene, and optimization of its expression in E. coli TOP10 was performed. KNOUC112 $\beta$-gal in pET-5b was isolated out, fused with thioredoxin gene in pThioHis C, and transformed to E. coli TOP10. The $\beta$-galactosidase fused with thioredoxin was produced in E. coli TOP10 as dimer and trimer. The productivity of fusion $\beta$ -galactosidase expressed via pThioHis C at 37$^{\circ}C$ was about 5 times higher than that of unfused $\beta$-galactosidase expressed via pET-5b at 37$^{\circ}C$. Inclusion body of $\beta$-galactosidase was formed highly, regardless of the induction by IPTG when KNOUC112 $\beta$ -gal was expressed via pET-5b at 37$^{\circ}C$. Fusion $\beta$ -galactosidase expressed at 37$^{\circ}C$ via pThioHis C without the induction by IPTG was soluble, but the induction by IPTG promoted the formation of inclusion body. Lowering the incubation temperature for the expression of fusion gene under 25$^{\circ}C$ prevented the formation of inclusion body, optimally at 25$^{\circ}C$. 0.07 mM of IPTG was sufficient for the soluble expression of fusion gene at 25$^{\circ}C$. The soluble production of Thermus thermophilus KNOUC112 $\beta$-galactosidase could be increased about 10 times by fusion with thioredoxin, and optimization of incubation temperature and IPTG concentration for induction.