• 한국식품영양과학회지
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• 제19권6호
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• pp.605-611
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• 1990

$\beta$-Galactosidase는 미숙감에서는 활성이 없었으나, 완숙감과 연시에서 각각 21.79, 380.23 unit/ 100g-fr. wt.이었으며 연시에서 현저히 증가하였다. $\beta$-Galactosidase는 isoenzyme이 존재하지 않았고, 분자량은 115,000dalton이었다. $\beta$-Galactosidase의 Km값은 1.84$\times$$10^{-2}$ mM, Vmax는 0.095 mmole p-nitrophenyl-$\beta$-galactoside degraded/$m\ell$/ 15min.이었고 최적 pH는 4.2. 최적온도는 45$^{\circ}C$이었으며, 6$0^{\circ}C$에서 10분간 열처리하였을 때 활성이 50%소실되었다. $\beta$-Galactosidase의 활성에 SDS는 저해하였으나 Mg++과 Ca++은 영향을 주지 않았다.

• 한국식품저장유통학회지
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• 제7권2호
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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.

• 한국축산식품학회지
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• 제27권1호
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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.

• 한국미생물·생명공학회지
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• 제18권6호
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• pp.566-570
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• 1990

Lactobacillus sporogenes에서 Beta-glactosidase의 생합성은 isopropyl-Beta-galactopyransoide(IPTG)나 galactose에 의해 효과적으로 유도되었으며 배양초기에는 lactose에 의해서도 훨씬 낮은 정도로 유도되었다. Glucose는 inducer exclusion이나 transient repression이 아니 catabolite repression에 의해 Beta-galactosidase의 합성을 억제시킴을 알 수 있었다. 또한, glucose에 의한 Beta-galactosidase의 catabolite repression은 cAMP나 cGMP에 의해 전혀 완하되지 않았다.

• 한국미생물·생명공학회지
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• 제42권4호
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• pp.339-346
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• 2014

가정에서 제조된 된장으로부터 lactose를 glucose와 galactose로 가수분해하는 균체외 ${\beta}$-galactosidase의 생산균이 분리되었다. 분리균 YB-1414는 형태적 특성, 생화학적 성질 및 16S rRNA 유전자 염기서열에 근거하여 Bacillus licheniformis로 확인되었다. 탄소원과 질소원으로 밀기울 (1%)과 yeast extract (2.5%)를 사용하였을 때 B. licheniformis YB-1414의 ${\beta}$-galactosidase 생산성이 최대 6.2 U/ml에 이르렀다. 특히 밀기울의 불용성 성분이 수용성 성분보다 ${\beta}$-galactosidase 생산성을 더 증가 시키는 것으로 확인되었다. ${\beta}$-galactosidase의 para-nitrophenyl-${\beta}$-D-galactopyranoside 가수분해 활성은 pH 6.0과 $55-60^{\circ}C$에서 가장 높았으며, 낮은 농도의 galactose에 의해서도 크게 저해를 받았다. 그러나 glucose에 의해서는 ${\beta}$-galactosidase의 가수분해 활성이 약하게 저해를 받으며 400 mM glucose가 존재하여도 최대 활성의 85%에 해당하는 가수분해 활성을 보였다.

• 한국미생물·생명공학회지
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• 제31권2호
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• pp.151-156
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• 2003

토양으로부터 세포외로 $\beta$-galactosidase를 분비 생산하는 방선균 YB-10이 분리되었으며, 분리균의 배양ㆍ형태ㆍ생리적 특성을 조사한 결과 Streptomyces속 균주로 확인되었다. 분리균의 배양상등액을 30%~70% ammonium sulfate로 처리하고 투석하여 얻은 $\beta$-galactosidase를 조효소액으로 사용하였을 때 para-nitrophenyl-$\beta$-D-galactopyranoside (pUP$\beta$Gal)는 pH 6.0과 6$0^{\circ}C$의 반응조건에서 가장 잘 분해되었으며, lactose는 galactose와 glucose로 가수분해되는 것으로 확인되었다. 분리균이 생산하는 $\beta$-galactosidase는 galactose에 의해 lactose와 pNP-$\beta$Gal의 가수분해 활성이 모두 저해되었으나, glucose에 의해서는 lactos의 가수분해 활성만 저해되었다. 특히 pUP-$\beta$Gal의 가수분해 활성은 glucose에 의해 약 1.8배 증진되었다.

• 한국미생물·생명공학회지
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• 제25권3호
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• pp.298-304
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• 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).

• 한국식품영양학회지
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• 제12권1호
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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%.

• 한국식품영양과학회지
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• 제21권1호
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• pp.60-63
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• 1992

본 실험은 yoghurt와 yoghurt culture에서의 ${\beta}-galactosidase$의 활성도를 측정하였다. Liquid medium에서 자란 yoghurt culture의 ${\beta}-galactosidase$의 활성도는 S. thermophilus가 Lactobacillus에 비해 $5{\sim}10$배 높은 것으로 나타났으며 제조 yoghurt를 저장온도에 따른 차이를 실험한 결과 냉장보관$(4^{\circ}C)$시 한달 정도까지는 효소활성도와 생균수를 보전함을 볼 수 있었으나 실온저장시는 5일 정도 밖에 효소활성도와 생균수를 유지하지 못했다. 실험을 통해 ${\beta}-galactosidase$ activity는 생균수와 비례함을, 특히 S. thermophilus의 생균수와 비례함을 알수 있었다. 시판 yoghurt와의 비교실험에서는 활성도와 생균수에 있어서 반정도의 수준도 못 미침을 알수 있었는데 이는 다음호에 계속될 여러 요인들에 기인함을 짐작케 한다.

• Journal of Microbiology and Biotechnology
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• 제11권1호
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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.