Lysozyme activity effects

The effect of ozone on lysosomal enzymes has been studied by a number of investigators. Ozone has been clearly shown to inactivate lysozyme in vitro, but the effects of inhaled ozone on the activity of lysozyme appear to depend on the pulmonary fraction under study. Holzman et al. reported that exposure of rabbits or mice to ozone resulted in a decrease in the lysozyme activity of bronchopulmonary lavage samples. The effect was linearly related to product of ozone concentration and duration of exposure, although relatively high concentrations of ozone (2.0-S.S ppm) were used in this acute-exposure experiment (1-4 h). The authors also reported that alveolar cells present in the bronchial lavage of rabbits exposed to ozone at 10 ppm for 3 h had a decrease in the rate of lysosomal... 

Continuous for 8 days Increased activity of lung and plasma lysozyme (no effect at 0.2 and 0.5 ppm) Rat 31... 

The assay principle is straightforward the clearance of a Micrococcus hocus suspension caused by lysozyme is monitored at 450 nm and compared to a lysozyme standard of known activity. Expression of lysozyme activity in absolute terms is dependent on the substrate sensitivity. Moreover (he light scattering effect of the suspension is determined by the optical geometry of (he spectrophotometer. Therefore, absolute turbidity values can only be obtained by calibration of the apparatus with a standard of known turbidity. 

Flarada M. 1977. Photochemical smog and tear fluid. [Effects [of smog] on pH, volume, and lysozyme activity of tear fluid.] Nipon Ganka Gakkai Zasshi 81.215- 286. (Japanese)... 

Low, K.W. and Y.M. Sin. Effects of mercuric chloride on chemiluminescent response of phagocytes and tissue lysozyme activity on tilapia, Oreochromis aureus. Bull. Environ. Contam. Toxicol. 54 302-308, 1995. 

With the interest in glycosidase inhibitors, compounds lending insight to the structures and mechanisms of these enzymes have received much attention. Recently, Lehmann, et al.,27 prepared a series of diastereotopic C-glycosides designed to be substrates for p-D-galactosidase. The premise was that in order to confirm this enzyme s mechanism of action, proposed from an extrapolation of lysozyme activity,28 31 the structural analysis of products resulting from the enzyme s effect on its substrates would be helpful. Therefore, the structures... 

Urinary lysozyme activity was also increased in workers e q)osed to an average of 23 ppm for about 9 years (Vyskocil et al. 1990). At imspecified exposure concentrations and durations, an increase in urinary fibronectin was observed in workers exposed to tetrachloroethylene (Bundschuh et al. 1993). No effects on urinary proteins (high and low molecular weight) or -acetyl-glucosaminidase (NAG) were observed. No effects on BUN or serum creatinine were observed in workers exposed at an average concentration of 20 ppm for 1-20 months (Cai et al. 1991), and occupational exposure to tetrachloroethylene at an average concentration of 14 ppm for an average of 12 years had no effects on... 

Some recent investigations have failed to substantiate earlier claims that NAA are effective as a result of, helr ability to stabilize lysosome membranes. It has been concluded, however, that lysosome membrane stability is very much dependent on experimental conditions and that in vitro methods using rat liver lysosomes are not sufficient for studying the effect of antiinflammatory drugs. Increased lysosomal enzyme activity in homogenates of rat paws paralleled increases in paw volume in rats with adjuvant-induced arthritis. Oral administration of phenylbutazone arrested Increases in both enzyme activity and paw edema. Above normal lysozyme activity was found in the serum and synovial fluid of a signlficent proportion of patients with RA. ... 

Lysozyme s application is directed primarily toward white wines for the control of LAB. Unlike compounds previously discussed, lysozyme exhibits activity toward all species and strains of LAB studied. At its suggested use level of 250-500 mg/L, the enzyme preparation may be added before alcoholic fermentation to prevent MLF, at some time during MLF, or upon completion to prevent subsequent activity of unwanted LAB. Its activity is not affected by ethanol, although upon reaction with tannin and pigment complexes, activity decreases (Villa, 1996). Similarly, bentonite dramatically decreases activity. In white juice, this ranged from 37% reduction after bentonite additions of 0.25 g/L to complete inactivation with additions of 1 g/L. In white wines, the impact of bentonite was less, ranging from 10% reduction with 0.25 g/L to 75% reduction at 1.0 g/L. The effect of sulfur dioxide additions in white wine was also investigated. In this case. Villa reports that SO2 at 80 mg/L had an indirect effect on lysozyme activity... 

P12 Pates, M. M. Effect of orotic acid lysozyme activity of the blood serum. Novoe Biokhim. Fiziol. Vitamin. Ferment, pp. 9-16 (1972) (CA 79 (1973) 51711w) (Russ.)... 

Fig. 5.16. Effect of different initial concentrations and ratio of GSSG and GSH on the extent of recovery of lysozyme activity (according to Saxena and Wetlaufer, 1970) (a) after 5 min (b) after 30 min. Regeneration conditions were 37°C, 0.08M Tris buffer at pH 8.0. Initial lysozyme concentration was 1 juA/. Enzymatic activity was measured on aliquots quenched at pH 5.0.

FIGURE 6.6. The type of model compounds that were used to estimate the electrostatic stabilization in lysozyme (the only hydrogen atom shown, is the one bonded to the oxygen). Such molecules do not show a large rate acceleration due to electrostatic stabilization of the positively charged carbonium transition state. However, the reaction occurs in solution and not in a protein-active site, and the dielectric effect is expected to be very different in the two cases. 

FIGURE 6.10. Comparing the energetics of the EVB configurations in solution and in the active site of lysozyme. The calculations were done by using the PDLD and related models (Refs. 6 and 7) and they represent a study of a stepwise mechanism. The energetics of a more concerted pathway (e.g., that of Fig. 6.9) is almost identical to that of the stepwise mechanism and correlated in a similar way with the electrostatic effect of the protein. 

Lower and coworkers [199] have investigated the adsorption of T4 lysozyme on colloidal silica. It was observed that the enzymatic activity decreased upon adsorption due to the differences in adsorbed enzyme structure and orientation as well as the electrostatic effects. 

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