• Asian-Australasian Journal of Animal Sciences
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• v.15 no.6
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• pp.895-899
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• 2002

Lysozyme activity in buffalo milk in relation to the period of lactation, parity of animal, weather conditions and udder infections was studied. Effect of storage and heat processing of milk on lysozyme activity was determined. Lysozyme activity was higher in buffalo milk than in cow milk. Buffalo colostrum showed lysozyme activity 5 times of that in mature milk. Lysozyme activity in buffalo milk was not influenced by the parity of animal and the stage of lactation, however, it increased during extreme whether conditions (winter and summer). Lysozyme in both cow and buffalo milk exhibited maximum activity at pH 7.4. Buffalo milk lysozyme was fully stable while the cow milk lysozyme was partly inactivated by pasteurization (low temperature-long time as well as high temperature-short time treatments). Lysozyme in buffalo milk was more stable than in cow milk during storage and heat treatment. A 10 to 50-fold increase in milk lysozyme activity was observed in mastitic cows. An assay of lysozyme activity in milk can be used to diagnose mastitis in cattle but not in buffaloes. Some buffaloes exhibited 1000 fold greater lysozyme activity and moderately raised somatic cell count in milk, but there was no sign of mastitis in these animals. A possible role of milk lysozyme in prevention of mastitis in buffaloes is discussed.

• Journal of Applied Biological Chemistry
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• v.61 no.4
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• pp.367-370
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• 2018

Lysozyme is an antibacterial enzyme that is found in most of body fluids. Lysozyme in tears plays a primary role in protecting eye from harmful environments; if lysozyme is degraded or inhibited, eyes are likely to be more vulnerable to bacterial infection. In this study, lysozyme activity was evaluated according to varying concentrations of heavy metals, copper, zinc, cobalt and manganese and light metal, calcium that are frequently found in airborne particulate matters and was assayed using a dye-quenching lysozyme substrate, Micrococcus lysodeikticus. Less fluorescence intensity was observed with increasing amounts of copper, zinc, manganese and cobalt but not with calcium suggesting that these metals have some affinity with lysozyme and inhibit lysozyme activity. When albumin, the second most common protein in tears, was added on the reaction of lysozyme and metals, lysozyme activity was partially restored. This finding suggests that the albumin might protect damage caused by metals on lysozyme. To identify whether the decrease in enzymatic activity was related to structural changes of lysozyme, SDS-PAGE was conducted and only with copper did lysozyme show marked smearing bands on the SDS-gel, meaning that copper degraded lysozyme consistent with the sharpest activity decrease.

• Textile Coloration and Finishing
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• v.30 no.4
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• pp.264-274
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• 2018

Immobilization of lysozyme on chitosan non-woven using glutaraldehyde(GA) was investigated. For this, 100 % chitosan non-woven was prepared as novel support for the enzyme immobilization. In addition, free lysozyme activity was examined depending on various pH and temperature by measuring time. Moreover, the optimum immobilization conditions depending on various pH, temperature, immobilization time and lysozyme concentration was evaluated. In addition, thermal stability and storage stability of immobilized lysozyme were measured. The characteristics of immobilized lysozyme was examined by FT-IR, surface morphology, and MTT assay. The results are follows: the optimal immobilization of lysozyme were pH 7.0, $25^{\circ}C$, lysozyme concentration 1.5 mg/ml, immobilization time 240 min. The immobilized lysozyme showed higher thermal stability than the free trypsin. The immobilized lysozyme activity was retained 80 % of its initial activity at $4^{\circ}C$ over 30 days of storage. The lysozyme was immobilized effectively on chitosan non-woven by observation of surface morphology.

• Preventive Nutrition and Food Science
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• v.3 no.4
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• pp.320-323
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• 1998

Lysozyme was covalentyl conjugated with galactomannan through a amino-carbonyl reaction between the lysine $\varepsilon$-amino groups of lysozyme and the reducing ends of galactomannan at a relative humidity of 79% and 6$0^{\circ}C$. The resulting lysozyme-galactomannan conjugate (LGC) was investigated for its antibacterial activity against Escherichia coli. Lysozyme alone did not exhibit antibacterial activity against E. coli. in contrast , significant bactericidal effect was observed for LGC, depending on the reaction temperature. The degree of conjugation between lysozyme and galactomannan was dependent on the incubation time, which affected the antibacterial efficiency against E. coli. This study demonstrated that the amino-carbonyl reaction between lysozyme and galactomannan could be a potential tool to modify lysozyme toward broadening its antibacterial spectrum to Gram-negative bacteria.

• Korean Journal of Poultry Science
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• v.17 no.2
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• pp.109-114
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• 1990

Enzymatic activity of isolated Lysozyme from egg white by cation ion-exchange chromatography was detected with various methods and stability of lysozyme in solution was studied by heat and pH treatments. Lysozyme activity refered to mg pure lysozyme/mg sample was more accurate although it needed standard lysozyme. But lysozyme activity refered to units/mg sample could be detected easily and reducted total detection time. Enzymatic activity of isolated lysozyme which dissolved in 0.066M phosphate buffer(pH 6.3) and then incubated at $37^{\circ}C$ for 2hr was increased remarkably on the lysis of Micrococcus lysodeikticus. The activity of isolated lysozyme by CM Sephadex C-25 was higher in eluting solution of above O. D. 1.0 at 640nm and attained 36, 000 units/mg solid. The stability of isolated lysozyme was decreased by various heat treatment. Activity began to decrease above 6$0^{\circ}C$ and dropped rapidly at $100^{\circ}C$. Especially, 35% loss of activity occured in 0.066M phosphate buffer at $100^{\circ}C$. for 15min. The stability of lysozyme was also affected by pH. lysozyme was very stable in acidic solution but in alkaline solution. Enzymatic activity showed maximum value at pH 3.0 solution while decreased rapidly above pH 6.0 solution.

• Applied Chemistry for Engineering
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• v.9 no.6
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• pp.857-863
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• 1998

A simple and new experimental method for determination of lysozyme-M. lysodeikticus cell lysis reaction and lysozyme activity was suggested using Beer's law. The UV transmittance of the solution changed with the concentration of M. lysodeikticus and the relationship between the UV transmittance and M. lysodeikticus cell concentration followed Beer's Law. In addition, it was experimentally proven that the UV transmittance of the solution was not influenced by the lysozyme concentration and product of the lysis reaction. During the lysozyme-M. lysodeikticus cell lysis reaction, thus, M. lysodeikticus cell concentration in the solution could be measured in-situ by UV-spectrophotometer. By using these experimental data, kinetic Parameters of the Michaelis-Menten equation for the lysozyme-M. lysodeikticus cell 1ysis reaction was simply determined The maximum reaction rate constant ($k_3$) and Michaelis-Menten constants were $0.1734sec^{-1}$ and $9.83{\times}10^{-6}M$ respectively. The activity of the lysozyme could also be obtained with this experiment because the lysis reaction rate of the 1ysozyme depended on its activity.

• Journal of Oral Medicine and Pain
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• v.33 no.1
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• pp.1-8
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• 2008

It is well known that many antimicrobial proteins in saliva interact with each other. The purpose of the present study was to investigate the interactions of lysozyme with peroxidase in the aspects of enzymatic activity in vitro. The interactions of lysozyme with peroxidase were examined by incubating hen egg-white lysozyme(HEWL) with bovine lactoperoxidase(bLP). The influence of peroxidase system on lysozyme was examined by subsequent addition of potassium thiocyanate and hydrogen peroxide. Lysozyme activity was determined by turbidity measurement of a Micrococcus lysodeikticus substrate suspension. Peroxidase activity was determined with an NbsSCN assay. The Wilcoxon signed rank test was used to analyze the changes of enzymatic activities compared with their controls. bLP at physiological concentrations enhanced the enzymatic activity of HEWL(P < 0.05) and its effect was dependent on the concentration of peroxidase. However, HEWL did not affect the enzymatic activity of bLP. Thiocyanate did not affect the enzymatic activity of HEWL, either. The addition of potassium thiocyanate and hydrogen peroxide did not lead to additional enhancement of the enzymatic activity of HEWL. The changes of hydrogen peroxide concentration in the peroxidase system did not affect the enzymatic activity of HEWL. Collectively, despite an in vitro nature of our study, the results of the present study provide valuable information on the interactions of lysozyme and peroxidase in the aspects of enzymatic activity in oral health care products and possibly in the oral cavity.

• Korean Journal of Environmental Biology
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• v.33 no.4
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• pp.476-483
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• 2015

We are aim to evaluate lysozyme and antibacterial activity of cultured catfish, Silurus asotus, that fed supplementally with Galla rhois extracts for eight weeks. Lysozyme activity in the spleen and serum of administrated group was higher than not administrated group, but in mucus of the lysozyme activity was no regular than other organ. The lysozyme activity of the spleen, kidney, serum of administrated fishes were increased after 2 weeks and that was highest after 8 weeks. Ht and GLU in serum of administrated fishes were gradually increased but GOT was decreased after 8 weeks. There is no significant differences in HB (Hemoglobin) and TP (Total Protein) each groups. Furthermore, there is no pathohistological changes of kidney and liver of tested fishes. The cumulative survival rates of administrated group after intraperitoneal injection of Aeromonas veronii with $6.5{\times}10^6cfu\;mL^{-1}$ was presented 33% in 9 days. As the Results, Galla rhois extracts has any beneficial effects for immunity elevation and antibacterial activity in catfish, Silurus asotus.

• Journal of Korean Ophthalmic Optics Society
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• v.2 no.1
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• pp.85-90
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• 1997

The cornea and conjunctiva of the human eye are exposed to external environment and thus are damageable. If the damaged part is infected with some pathogenic microorganisms. serious visual loss may be occured by inflammation. Keratitis or conjunctivitis does not always occur if the eyes are routinely exposed to pathogenic factors because lysozyme in human tears has antimicrobial activity against the microorganisms. 10 this study we have selected 5 strains causing keratitis and/or conjunctivitis. and cultured them in the optimum media. And then we have estimated the growth inhibition of the strains with the addition of various concentration of lysozyme to media to investigate the antimicrobial activity of lysozyme. The results are as follows. The growth of the strains were decreased according to the increase of lysozyme concentration. The growth of Pseudomonas. Neisseria. Klebsiella and Staphylococcus were inhibited 43%, 41%, 35% and 22% respectively by 1 mM concentration of lysozyme. The susceptibility of the gram-negative bacteria to lysozyme is 1.5~2 times higher than the Staphylococcus which is gram-positive bacteria in 1 mM concentration of lysozyme. But lysozyme inhibited the growth of Fusarium which is fungi slightly.

• The Korean Journal of Food And Nutrition
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• v.9 no.4
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• pp.447-451
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• 1996

Lytic activities of the egg white lysozyme from Korea-native Ogol fowl against the alkalophilic and thermophilic Bacillus sp. TA-11 were investigated and compared. Lytic activity of the Ogol fowl lysozyme for Bacillus sp. TA-11 was the highest for the cell of post-logarithm phase and optimum concentration of the lysozyme was 0.25%, Optimum reaction pH and temperature were 4.5 and 35$^{\circ}C$, respectively. Lytic activity of egg white lysozyme from fowl for Bacillus sp. TA-11 was the highest for the cell of stationary phase and optimum concentration of the lysozyme was 0.5%. Optimum reaction pH and temperature were 5.5 and 4$0^{\circ}C$, respectively.