Extracellular cellulolytic enzyme system of Aspergillus japonicus: 1. Effect of different carbon sources
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Abstract α‐Amylase of the thermophilic actinomycete Thermomonospora vulgaris was partially purified. Maximal enzyme activity was obtained at 60 °C and pH 6.0. K M value was 1.4%. The effect of some metal salts on enzyme activity was studied. Enzyme activity was inhibited by KCN, EDTA, and iodoacetate. Inhibition by EDTA was completely nullified by CaCl 2 , but the inhibition by iodoacetate was not overcome by 2‐mercaptoethanol. Exposure of the enzyme to pH 7.0 and 9.0 for 2hr. did not affect the enzyme, but exposure to pH 3.0 for few minutes completely inactivated the enzyme. Exposure of the enzyme to 60 °C resulted in an appreciable inactivation and exposure to 80 °C completely inactivated the enzyme. Addition of CaCl 2 , 2‐mercaptoethanol, or enzyme substrate did not stabilize the 60 °C exposed enzyme. However, bovine serum albumin had a protective effect when the enzyme was exposed to 60 °C but not to 80 °C. The enzyme was stable in the presence of 8 M urea.
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In this study, we evaluated optimum condition of enzyme with pH and temperature for preparation of microfibillated cellulose(MFC). Well-known endo-glucanase, three enzymes were used and CMC was used for substrate. Enzyme activity was evaluated using DNS method and absorbance with UV/VIS spectrophotometer. The enzyme shown the greatest activity was reacted with pulps at optimum condition for 1 hour and treated pulps beated until 100 mL CSF. Enzyme B and Enzyme L was the higher enzyme activity below 0.1% concentration and Enzyme N was the lowest enzyme activity. At various pH and temperature conditions, enzyme activity of Enzyme B was higher than the others at the same concentration. Especially enzyme activity at 50℃ of Enzyme B was almost not changed over pH 6.0. Optimum condition of three enzyme was pH 6 or pH 7 and 50℃or 60℃. Also beating efficiency of enzyme treated pulps with Enzyme B is 55.6%.
Absorbance
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Chalcone
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e studied the effect of temperature, enzyme concentration and pH on enzyme activity. The enzyme we studied was hydrogen peroxidase from a cow. The reaction converted hydrogen peroxide to water and oxygen and oxygen production was used as a measure of enzyme activity. We studied enzyme activity at temperatures of 9 C, 37 C, 41 C. It showed that at 9 C, there was almost no activity. The activity at 41 was 1.5X the activity at 37. The enzyme was tested using 1⁄2X, 1X and 2X enzyme concentration. Significant enzyme activity was seen at 1x enzyme concentration and the 1⁄2X enzyme concentration trial showed almost the same activity. The activity at 2X enzyme concentration was approximately 2 times that at 1X enzyme concentration. Finally, we tested the effect of pH on the enzyme with pH 7, pH 1 and pH 11. The enzyme activity was highest at neutral pH (7) and showed only 1/3 enzyme activity at pH 11while pH of 1 showed no enzyme activity. Introduction: Enzymes are catalysts or chemical agents that speed up chemical reactions without being consumed by the reaction (Reece et al. 2010). Most enzymes are proteins that function to reduce activation energy in chemical reactions (Petersen and Anderson 2005). Enzymes work on reactants called substrate; the enzyme attaches to the substrate and then the enzyme converts the substrate to products while the enzyme remains unaffected (Reece et al. 2010). Enzyme activity can be affected by environmental factors (Petersen and Anderson 2005). Temperature is one environmental factor that can affect enzyme activity (Conant 2012). Another factor that affects enzymes is pH (Leake and Read 1990). In this lab, we will be studying the effects of temperature, enzyme concentration and pH on the enzyme, hydrogen peroxidase that is found in all aerobic cells and functions to decompose hydrogen peroxide (Petersen and Anderson 2005). Materials and methods: A strip of filter paper was dipped into a cow liver homogenate for 10 seconds and then placed in a chamber. 20 mL of 1.5% H2O2 was added to the chamber and the chamber was plugged with a stopper and then placed in a water bath. After 5 minutes, a 50 mL graduated cylinder filled with water was overturned over the chamber to flow the H2O2. Measurements of oxygen released were taken at 5 second intervals for one minute for each trial. This experiment was done with three different variables: Temperature, enzyme concentration and pH. The temperatures tested were: 9 C, 37 C, 41 C. The enzyme concentration was done using 1⁄2 strip, 1 strip and 2 strips of filter paper (representing 1⁄2X, 1X and 2X enzyme concentration) keeping the temperature at 37 C. The pH test was done using 1 strip with 5 drops of 50% HCl added to the H2O2 to produce a pH of 1. Another pH test was performed by adding 5 drops of 50% NaOH to the H2O2 to yield a pH of 11. The third trial was kept at pH 7. The temperature for the pH trials was at 37 C. W 1 Eed: Factors Affecting Enzyme Activity Produced by The Berkeley Electronic Press, 2013
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Dynamic variation of extracellular enzyme activity ,extracellular polysaccharide and other relative target during the submerged culture of Corilus versicolor were investigated. The results showed that the maxmum of hypha growth was 6.436 g/L, appeared in the 12th days .There was not significant change of pH of the fluid medium through the whole period of the cultivation. The maxmun of extracellular protein consistencey was 1.06 mg/mL, appeared in the 11th days. The peak of guaicaal oxidase enzyme production appeared in the 12th days, the maxmum enzyme activity was 713.2 u. The peak of enzyme production of polyphenol oxidase appeared twice. The first appeared in the 12th days, and its enzyme activity was 660.1 u. The second appeared in the 18th days, its enzyme activity was 1001.0 u . Extracellular polysaccharide appeared its maxmum in the 12th days, it was 23.70 mg/L.
Extracellular polysaccharide
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Fucosidase
Specific activity
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alpha-Amylase of the thermophilic actinomycete Thermomonospora vulgaris was partially purified. Maximal enzyme activity was obtained at 60degreeC and pH 6.0. KM value was l.4%. The effect of some metal salts on enzyme activity was studied. Enzyme activity was inhibited by by KCN, EDTA, and iodoacetate. Inhibition by EDTA was completely nullified by CaCl2, but the inhibition by iodoacetate was not overcome by 2-mercaptoethanol. Exposure of the enzyme to pH 7.0 and 9.0 for 2 hr. did not affect the enzyme, but exposure to pH 3.0 for few minutes completely inactivated the enzyme. Exposure of the enzyme to 60degreeC resulted in an appreciable inactivation and exposure to 80degreeC completely inactivated the enzyme. Addition of CaCl2, 2-mercaptoethanol, or enzyme substrate the 60degreeC exposed enzyme. However, bovine serym albumin had a protective effect when the enzyme was exposed to 60degreeC but not to 80degreeC. The enzyme was stable in the presence of 8 M urea.
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Extracellular polysaccharide
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A strain producing fibrinolytic enzyme was isolated from starter.The strain was identified as Rhizopus micro-sporus var.tuberosus based on the morphological and ITS sequence.The enzymatic properties of the fibrinolytic enzyme secreted by the strain were determined.The properties tests suggest that the optimum temperature and pH were 37,℃ and 7.0r,espectively.The enzyme retained 95% of its initial activity by retaining for 4 h at 37,℃,and when it was treated at 57 ℃ for 4 h,the enzyme was still remained of activity.The enzyme had a wide range of pH adaptabilityi,t still remained of part of activity when pH was adjusted to a level(pH3.4);and it remained enzyme activity in between the range of pH 6.0-8.0.Zn2+ and Cu2+ have a very clear function to restrain the enzyme activity whereas Na+,Ca2+,Mn2+ showed obvious stimu-lation on the enzyme.The results show that the enzyme is stable in the artificial intestinal juicei,t retained 80% of its initial activity by retaining for 4 h at 37,℃.It may be developed to injection used in clinical research.
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