• Korean Journal of Food Science and Technology
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• v.30 no.6
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• pp.1426-1431
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• 1998

The research was undertaken to characterize enzymatic properties of Streptomyces albus amylase expressed in recombinant Bacillus subtilis. Molecular weight and pI of the purified enzyme were estimated to be 50 kD by SDS-PAGE and 4.3 by isoelectric focusing. The optimum temperature and optimum pH were $45^{\circ}C$ and 6.0, respectively. D-and Z-value were estimated to measure thermostability of the purified enzyme. The Z-value was estimated $17.7^{\circ}C$, which is lower than typical amylase. Maltotetraose was produced as a major component from soluble starch in the early state of reaction but gradually degraded to maltose. Thin layer chromatography was also performed to analyze the reaction products. The parameters involved in Michaelis-Menten enzyme kinetics were found to be the maximum velocity of 0.37 mM/min and the Michaelis constant of 0.13%, respectively.

• Reproductive and Developmental Biology
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• v.35 no.4
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• pp.441-447
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• 2011

The study aim is to investigate the free radicals scavenging and spermatogenic potentials, as well as to analyze any reproductive toxicity of ethanolic extract of Mucuna prureins (M. pruriens) Linn. in spermatozoa, under different dosages in normal male rat. Normal rats were randomly selected and suspension of the extract was administered orally at the dosages of 150, 200 and 250 mg/kg body weight of the different groups of male rats (n=6) once in a day for 60 days and grouped as group II, III and IV respectively. Saline treated rats served as control -group I. On the $60^{th}$ day the animals were sacrificed and the epididymal sperm were subjected to various analyses like level of ROS production, LPO, enzymatic and non enzymatic antioxidant, morphology, morphometry, chromosomal integrity and DNA damage. Results showed significant reduction in ROS production and peroxidation and significant increase in both enzymic and non-enzymic antioxidants in all concentration treated groups when compared with control. Results from all the drug treated groups showed good sperm morphology, increased sperm count and motility. There was no DNA damage and showed normal chromosomal integrity even in 250 mg/kg dose. When compared with control all the three extract treated groups showed increased ROS scavenging activity. However, group II (200 mg/kg) showed significant changes in all the parameters. From the present study it was confirmed that the M. pruriens has potential to improve the sperm qualitatively and quantitatively through scavenging the excess ROS with any adverse side effects. These observations suggest that ethanolic seed extract of M. pruriens may serve as anti-oxidant that can exploit to treat the oxidative stress mediated male factor infertility.

• Korean Journal of Food Science and Technology
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• v.42 no.1
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• pp.39-44
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• 2010

The process of the preparation of branched-chain amino acid (BCAA)-enriched hydrolysates from corn gluten was optimized through the parameters of pre-treatment (heating and cellulosic hydrolysis), hydrolysis method (acid, protease, and microbe plus protease), concentration, and spray drying condition. The protein yield of corn gluten was increased by heating and cellulase treatments. Among three different hydrolysis methods, the combined use of microbes and protease was the most effective in terms of free amino acid (FAA) and BCAA content of the corn gluten hydrolysates. In addition, the FAA and BCAA content in the hydrolysates prepared by microbial and enzymatic combined treatment were improved by a concentration process. Spray drying conditions for the preparation of the powder from the hydrolyzed reactant were an inlet temperature of $185^{\circ}C$, outlet temperature of $80^{\circ}C$, and the use of maltodextrin as an anticaking agent. Thus, this study established an economical process for preparation of value-added hydrolysates of excellent productivity and quality, in terms of high BCAA content and product stability.

• Journal of Microbiology and Biotechnology
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• v.22 no.3
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• pp.292-300
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• 2012

We report the expression, purification, and characterization of L-asparaginase (AnsA) from Rhizobium etli. The enzyme was purified to homogeneity in a single-step procedure involving affinity chromatography, and the kinetic parameters $K_m$, $V_{max}$, and $k_{cat}$ for L-asparagine were determined. The enzymatic activity in the presence of a number of substrates and metal ions was investigated. The molecular mass of the enzyme was 47 kDa by SDS-PAGE. The enzyme showed a maximal activity at $50^{\circ}C$, but the optimal temperature of activity was $37^{\circ}C$. It also showed maximal and optimal activities at pH 9.0. The values of $K_m$, $V_{max}$, $k_{cat}$, and $k_{cat}/K_m$ were $8.9{\pm}0.967{\times}10^{-3}$ M, $128{\pm}2.8$ U/mg protein, $106{\pm}2s^{-1}$, and $1.2{\pm}0.105{\times}10^4M^{-1}s^{-1}$, respectively. The L-asparaginase activity was reduced in the presence of $Mn^{2+}$, $Zn^{2+}$, $Ca^{2+}$, and $Mg^{2+}$ metal ions for about 52% to 31%. In addition, we found that $NH_4{^+}$, L-Asp, D-Asn, and ${\beta}$-aspartyl-hydroxamate in the reaction buffer reduced the activity of the enzyme, whereas L-Gln did not modify its enzymatic activity. This is the first report on the expression and characterization of the L-asparaginase (AnsA) from R. etli. Phylogenetic analysis of asparaginases reveals an increasing group of known sequences of the Rhizobial-type asparaginase II family.

• KSBB Journal
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• v.13 no.2
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• pp.147-154
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• 1998

Enzymatic hydrolysis using an immobilized enzyme was carried out to produce chitosan oligosaccharides (COSs) from chitosan effectively. Chitosanase was immobilized on eight different carriers by physical adsorption. The enzyme immobilized on chitin had higher activity than those immobilized on the other carriers in spite of its lower adsorption. The activity of chitin-immobilized enzyme was more than 90% of the original activity. Optimal temperature of the immobilized enzyme increased by about $15^{\circ}C$ and its thermostability was excellent in relatively wide range of temperature. But its effects of pH did not improve compared to the free enzyme. The immobilized enzyme produced 153 mg/g chitosan of the reducing sugar for 3hrs of hydrolytic incubation time. The total content of higher oligomers, tetramer to hexamer, among amount of total COSs obtained for 2hrs was more than 90%. In kinetic parameters for both enzymes, immobilized enzyme showed lower affinity for substrate and reaction rate than free enzyme, however, no reduction of the rate for high substrate concentrations. Consequently, chitin-immobilized could effectively hydrolyse chitosan and produce the higher COSs without activity decrease in comparison with the free enzyme.

• Korean Journal of Food Science and Technology
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• v.16 no.2
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• pp.211-217
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• 1984

To study affinity of proteolytic enzymes to soy proteins, the physicochemical and functional properties of enzymatically modified protein products, kinetic parameters and degree of hydrolysis were measured using trypsin, alcalase (serine type protease) and pronase. Bacterial alcalase and pronase showed much greater affinity to soy protein than animal intestinal trypsin. This effect was very significant when unheated soy isolate was used as a substrate. Specific activities of these enzymes decreased with the increment of substrate concentration (over 2.0%, w/v) when heat denatured soy protein was used as a substrate. However, the decrease in specific activity was negligible at substrate concentrations lower than 2.0%. Polyacrylamide gel electrophoretic results showed that the pattern of 2S protein band changed distinctly in alcalase hydrolysis as compared with those of trypsin and pronase. Protein solubilities of alcalase and pronase hydrolyzates increased by 25-30%, at their pI (pH 5.0) over the control. Virtually no change was observed in solubility by trypsin hydrolysis. Heat coagulability and calcium-tolerance of the protein increased by enzymatic hydrolysis. No clear tendency, however, was observed for emulsion properties, foam expansion and the amount of free -SH groups. The enzyme treatment considerably decreased foam stability.

• Korean Journal of Environmental Biology
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• v.38 no.1
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• pp.40-46
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• 2020

Hybrid grouper(Epinephelus fuscoguttatus ♀×E. lanceolatus ♂) (mean weight 25.7±3.5g, mean length 11.2±0.9cm) were exposed to different ammonia concentrations of 0, 5, 10, 20, and 40mg L^-1 for 96 hours. The hematological hematocrit and hemoglobin parameters of the hybrid grouper were significantly decreased by 20 mg L^-1 ammonia exposure. In the organic plasma components, calcium was significantly decreased, whereas there was no change in magnesium. In the organic plasma components, the glucose and cholesterol values of the hybrid grouper were significantly increased by ammonia exposure. In the enzymatic plasma components, the ALP(Alkaline phosphatase) value of the hybrid grouper was also significantly increased by ammonia exposure. The results of this study demonstrate that acute ammonia exposure to hybrid grouper induced changes in hematological parameters and plasma components. Therefore, acute ammonia exposure over 20 mg L^-1 appears to be toxic to hybrid grouper and the results can be used as a major indicator in breeding hybrid grouper.

• Journal of Chest Surgery
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• v.27 no.3
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• pp.177-186
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• 1994

Pentastarch is a hydroxyethyl starch similar to hetastarch, but lower average molecular weight and fewer hydroxyethyl groups which result in enhanced enzymatic hydrolysis and faster renal elimination.This report was performed to compare the clinical efficacy and safety of 10 % pentastarch[Pentaspan , group I] for plasma volume expansion after open heart surgery with that of 5% albumin[Plasmanate, group II]. There were no statistically significant differences between the group I [n=18] and group II [n:19] in the preoperative parameters [age, sex, body weight] and operative parameters[bypass time, aorta cross clamping time]. During the first 24 hours after arrival of the patient in the surgical intensive care unit, colloid solution [500--1000 ml] was infused to maintain left atrial pressure of more than 8 mmHg, or cardiac index of 2.0 L/min/M2 of more. In results, there were 3 complications of hypotension immediately after infusion of 5 % albumin solution and 2 among the 3 patients were excluded for the study. However there was no complication after infusion of 10 % pentastarch solution. Hemodynamic responses to infusion was similar for both groups, although in group I a greater increase in both left atrial pressure[mean 1.8 versus 0.7 mmHg, p< 0.05] and right atrial pressure [mean 2.2 versus 1.7 mmHg, p < 0.05] was observed during infusion of the first 500 ml. There were no significant differences in any of the measured respiratory parameters[PaO2, intrapulmonary shunt, and effective lung compliance]. Homodilution with colloid significantly reduced hemoglobin [mean 1.2 versus 0.8 gm/dl], and serum protein and albumin level[total protein;4.8$\pm$ 0.5 versus 5.2 $\pm$0.5 gm/dl, p < 0.05: albumin: 3.2 $\pm$0.4 versus 3.6 $\pm$0.6 gm/dl, p < 0.05] by 6:00 AM on 1 day postoperatively, however there were no significant differences on 7 day postoperatively. The mean serum colloid osmotic pressure and osmolarity was similar in both group.There were no abnormal findings of liver function and kidney function in all the patients. There were no significant between-group differences in bleeding time, platelets, prothrombin time, activated partial thromboplastin time and amount of chest tube output measured on 1st and 7th postoperative day. These findings demonstrated that 10% pentastarch is more effective and safe for plasma volume expension than 5 % albumin solution with no adverse effects on coagulation. Also 10 % pentastarch is less expensive than 5 % albumin and it would appeare to be a reasonable first choice for plasma volume expansion.

• Asian-Australasian Journal of Animal Sciences
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• v.12 no.1
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• pp.113-128
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• 1999

Protozoa can represent as half of the total rumen microbial biomass. Around 10 genera are generally present on the same time in the rumen. Based on nutritional aspects they can be divided in large entodiniomorphs, small entodiniomorphs and isotrichs. Their feeding behaviour and their enzymatic activities differ considerably. Many comparisons between defaunated and refaunated animals were carried out during the last two decades to explain the global role of protozoa at the ruminal or animal levels. It is now generally considered that a presence of an abundant protozoal population in the rumen has a negative effect on the amino acid (AA) supply to ruminants and contribute to generate more methane but, nevertheless, protozoa must not be considered as parasites. They are useful for numerous reasons. They stabilise rumen pH when animal are fed diets rich in available starch and decrease the redox potential of rumen digesta. Because cellulolytic bacteria are very sensitive to these two parameters, protozoa indirectly stimulate the bacterial cellulolytic activity and supply their own activity to the rumen microbial ecosystem. They could also supply some peptides in the rumen medium which can stimulate the growth of the rumen microbiota, but this aspect has never been considered in the past. Their high contribution to ammonia production has bad consequences on the urinary nitrogen excretion but means also that less dietary soluble nitrogen is necessary when protozoa are present. Changes in the molar percentages of VFA and gases from rumen fermentations are not so large that they could alter significantly the use of energy by animals. The answer of animals to elimination of protozoa (defaunation) depends on the balance between energy and protein needs of animals and the supply of nutrients supplied through the diet. Defaunation is useful in case of diets short in protein nitrogen but not limited in energy supply for animals having high needs of proteins.

• Journal of Microbiology and Biotechnology
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• v.30 no.3
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• pp.391-397
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• 2020

In this study, we used a novel α-L-arabinopyranosidase (AbpBs) obtained from ginsenoside-converting Blastococcus saxobsidens that was cloned and expressed in Escherichia coli BL21 (DE3), and then applied it in the biotransformation of ginsenoside Rb₂ into Rd. The gene, termed AbpBs, consisting of 2,406 nucleotides (801 amino acid residues), and with a predicted translated protein molecular mass of 86.4 kDa, was cloned into a pGEX4T-1 vector. A BLAST search using the AbpBs amino acid sequence revealed significant homology with a family 2 glycoside hydrolase (GH2). The over-expressed recombinant AbpBs in Escherichia coli BL21 (DE3) catalyzed the hydrolysis of the arabinopyranose moiety attached to the C-20 position of ginsenoside Rb₂ under optimal conditions (pH 7.0 and 40℃). Kinetic parameters for α-L-arabinopyranosidase showed apparent K_m and V_max values of 0.078 ± 0.0002 μM and 1.4 ± 0.1 μmol/min/mg of protein against p-nitrophenyl-α-L-arabinopyranoside. Using a purified AbpBs (1 ㎍/ml), 0.1% of ginsenoside Rb₂ was completely converted to ginsenoside Rd within 1 h. The recombinant AbpBs could be useful for high-yield, rapid, and low-cost preparation of ginsenoside Rd from Rb₂.