• The Korean Journal of Food And Nutrition
• /
• v.9 no.3
• /
• pp.247-252
• /
• 1996

$\beta$-Amylase was purified from sweet potato by acetone fractlonatlon, Sephadex A-50 ion exchange chromatography and Sepgadex G-200 gel chromatographyl The higher enzyme concentration was, the higher heat stability of enzyme became. After 1 hour 30 minute. At 6$0^{\circ}C$ in pH 5, enzyme under concentration of 30$\mu$l/ml lost its activity completely and over the concentration of 100$\mu$g/ml remained 25% of activity. The enzyme was stabilized at range of pH 4~10 and pH stability was increased by glycerol. Five moles of NaCl inhibited completely of the enzyme activity. SDS of 0.05% inhibited the enzyme completely after 12 hours at 37$^{\circ}C$ in pH5. One mole guanidine-HCl and 8M urea inhibited the entire enzyme after 13 hours at 37$^{\circ}C$ in pH 5.

• Archives of Pharmacal Research
• /
• v.13 no.1
• /
• pp.33-37
• /
• 1990

The effects of pH values, temperature and some elements on the amylolytic activity and stability of the purified S. aureofacienc 77 amylase were studied in this investigation. The purified enzyme showed its maximum activity at pH 6 within 8 min incubation at $40^{\circ}C$. None of the tested 6 metals showed on stimulatory effect on the enzymatic activity, $Fe^{+++}$, $Cu^{++}$ and $Hg^{++}$ at high dose inhibited the enzyme activity to great extent as compared with $Zn^{++}$, $Mn^{++}$ and $Fe^{++}$ whih gave less effect in this respect. The enzyme liquor was found to be thermolabile, since it lost completely its activity after 4 days incubation under room temperature and showed maximum activity during this period as a result of additions of $Ca^{++}$and NaCl, Gradual reduction was however recorded until activity reached 30% after 60 days of incubation.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.38 no.6
• /
• pp.812-815
• /
• 2009

The effects of processing conditions on the ${\alpha}$-amylase activity of radish were investigated at various temperatures, pHs and drying conditions. The ${\alpha}$-amylase activity of radish root was 3.1-fold higher than that of radish trunk. As the freeze-dried radish was incubated at various temperatures and pHs, ${\alpha}$-amylase activity was stably maintained at pH range of $4{\sim}7$ and temperature of $25{\sim}40^{\circ}C$. When radish was processed to kakdugi and danmooji, the residual ${\alpha}$-amylase activity was 45.39% and 19.19%, respectively. Consequently, the ${\alpha}$-amylase activity was greatly affected by processing conditions such as heat treatment and pH. It is suggested that radish should be processed at below $60^{\circ}C$ and at neutral to acidic pH condition.

• Journal of Microbiology and Biotechnology
• /
• v.14 no.6
• /
• pp.1196-1199
• /
• 2004

A bacterium, isolated from rabbit's waste and identified as Cellulomonas sp., had cellulase and thermostable $\alpha$-amylase activity when grown on wheat bran. Maximum activity of thermostable $\alpha$-amylase was obtained by adding $3\%$ soluble starch. However, soybean oil (1 ml $1^{-1}$) could increase the production of $\alpha$-amylase and cellulase in 'wheat bran. The $\alpha$-amylase was characterized by making a . demonstration of optimum activity at $90^{\circ}C$ and pH 6- 9, with soluble starch as a substrate. The effect of ions on the activity and the stability of this enzyme were investigated. This strain secreted carboxymethyl cellulase (CMCase), cellobiase ($\beta$­glucosidase), and filter paperase (Fpase) during growth on wheat bran. Carboxymethy1cellulase, cellobiase, and Fpase activities had pH optima of 6, 5.5, and 6, respectively. CMCase and cellobiase activities both had an optimum temperature of $50^{\circ}C$, whereas Fpase had an optimum temperature of $45^{\circ}C$.

• Journal of Pharmaceutical Investigation
• /
• v.21 no.3
• /
• pp.143-147
• /
• 1991

${\alpha}-amylase$ was immobilized on the surface of polyethylene glycol(M.W. 2000) grafted polyurethane film using diisocyanate in an attemp to develop enzyme immobilized polymeric materials. The surface morphology of the modified polyurethane film was examined by SEM. Effects of pH and temperature on the activity of the immobilized ${\alpha}-amylase$ were investigated. The optimal pH range of the activity was $7.0{\sim}7.5.$ The immobilized ${\alpha}-amylase$ demonstrated high thermal stability and maintained consistent activity during long-term storage.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.19 no.6
• /
• pp.591-595
• /
• 1990

A promoting effect of ginseng saponin on the growth recovery rate of Saccharomyces rouxii which was treated by heat was confirmed in previous report(22). In order to deduce the promoting effect on the growth recovery of the heat stressed yeast, the effect of ginseng saponin on the activity and the heat stability of the amylase produced by Sacchirromyces rouxii were observed. The amylase showed the highst activity at 0.01％ of saponin. At this concentration, the activity increased about 23％ compared to the control. Furthermore, the ginseng saponin showed a protective effect against thermal inactivation of the amylase produced by Saccharomyces rouxii.

• Journal of Microbiology and Biotechnology
• /
• v.2 no.3
• /
• pp.166-173
• /
• 1992

The expression of Bacillus subtilis $\alpha$-amylase from the phoA-amyE fusion gene in recombinant E. coli was investigated under various environmental conditions. The overexpression of cloned $\alpha$-amylase caused retardations in cell growth and synthesis of alkaline phosphatase (AP) from the chromosomal phoA gene. The change of culture temperature from $37^\circ{C}$ to $30^\circ{C}$ increased the specific activities of both $\alpha$-amylase and $\beta$-lactamase by six and two times, respectively, whereas the AP activity remained unchanged. The experiments with chlorampenicol (a translation inhibitor) suggested the enhancement of $\alpha$-amylase activity at $30^\circ{C}$, and this was partly due to the stability of $\alpha$-amylase itself. The further decrease of the temperature to $25^\circ{C}$ slowed down both the cell growth and cloned-gene expression rate. The $\alpha$-amylase activity showed a maximum at pH of 7.4 while alkaline phosphatase was most effectively produced at pH of 8.3.

• The Korean Journal of Food And Nutrition
• /
• v.9 no.3
• /
• pp.253-258
• /
• 1996

Stabilities of sweets potato f-amylase on various reagents were studied. The enzyme was stabilized by bovine serum albumin, Triton X-100 and 2-mercaptoethanol of 0.04%. Among them, bovine serum albumin was the most effective. And enzyme stability was increased by using the deairated solution. The enzyme activity was remained 0% in the absence of glycerol, 25% in the presence of 20% glycerol and 50% in the presence of 40% glycerol at 37$^{\circ}C$, for 15 hours in pH 11. SDS inhibited the enzyme, and 2-mercaptoethanol and dithiothreitol stabilized it.

• Applied Biological Chemistry
• /
• v.21 no.2
• /
• pp.103-108
• /
• 1978

Acid-stable ${\alpha}-amylase$ was partially purified from Paecilomyces subglobosum by Sephadex G-150 gel filtration. About 7.7-fold purification was obtained and the partially purified preparation has 5.0 U of ${\alpha}-amylase$ activity per mg of protein. Using this partially purified ${\alpha}-amylase$, general properties were studied and it showed the maximal activities at the conditions of pH 4.0 and $38^{\circ}C$. High stability of the acid-stable ${\alpha}-amylase$ in acidic condition was observed, whereas thermal stability was similar to the conventional ${\alpha}-amylase$.

• YAKHAK HOEJI
• /
• v.6 no.2
• /
• pp.18-22
• /
• 1962

Purified preparation of .betha.-amylase is obtained from radish root by the means of fractional precipitation with ammonium sulfate. Purified preparation saccharifies the starch, .betha.-maltose being formed. Dextrinization in the true sense does not take place. Hydrolysis ceases when approximately 50% of the theoretical yield of maltose is obtained and there remains a substance (to be .betha.-limit dextrin) which gives a blue-violet with iodine, no glucose being formed. Stability of preparation is optimal at pH 4-9 and more completely inactivated at 65.deg. in fifteen minutes. .betha.-Amylase of radish exhibits optimal activity at and near pH 5.0, which varied depending upon the buffer. Calcium and chloride ions do not effect the activities of enzyme. The results of experiments with oxidizing, alkylating and mercaptide-forming reagents which have been reported to be specific for sulfhydryl groups confirm that free sulfhydryl groups are essential to the activity of .betha.-amylase from radish.