Cell lysis, kinetics, lysozyme

A. Lysozyme Occurrence, Isolation, and Kinetics of Cell Lysis. 181... 

Although extended reaction time was also used by Selsted and Martinez (1980) in their turbidimetric method, they did not stress the importance of the kinetic order of cell lysis. McKenzie and White (1986) showed that, while the reaction is biphasic, simple kinetics are obeyed over a sufficiently long period that this property can be exploited in the determination. The kinetic order must be considered in the quantitative treatment of the results. The limit of detection was found to be 100 pg ml of reaction mixture, equivalent in the case of bovine milk lysozyme to 6 ng ml of skim milk, for a 50-/xl sample. 

The influence of colloidal forces on reactions involving Immobilized enzymes acting on Insoluble substrates has received less attention, yet it appears to offer some clear examples of fundamental phenomena important in enzyme kinetics. Datta examined lysis of Micrococcus Ivsodelktlcus by soluble and (polyacrylamide) immobilized lysozyme. He noted that the decrease in soluble enzyme activity with decreasing ionic strength (Table 1) paralleled the measured decrease in cell lysis measured in flow through a packed bed reactor of Immobilized enzyme. 

Thus, investigation of the kinetics of lysozyme-catalyzed lysis of bacterial cell walls has shown that the presence of an organic solvent decreased the overall reaction rate reversibly with the rados of the maximum rate constant of lysis in water and in mixed solvent given by... 

In one case, a small peptide with enzyme-like capability has been claimed. On the basis of model building and conformation studies, the peptide Glu-Phe-Ala-Ala-Glu-Glu-Phe-Ala-Ser-Phe was synthesized in the hope that the carboxyl groups in the center of the model would act like the carboxyl groups in lysozyme 17). The kinetic data in this article come from assays of cell wall lysis of M. lysodeikticus, chitin hydrolysis, and dextran hydrolysis. All of these assays are turbidimetric. Although details of the assay procedures were not given, the final equilibrium positions are apparently different for the reaction catalyzed by lysozyme and the reaction catalyzed by the decapeptide. Similar peptide models for proteases were made on the basis of empirical rules for predicting polypeptide conformations. These materials had no amidase activity and esterase activity only slightly better than that of histidine 59, 60). 

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