Specificity of cell-envelop proteinase of lactococci toward the casein fractions
Journal Title: Біологія тварин - Year 2015, Vol 17, Issue 3
Abstract
The specificity of cell-envelop proteinases of lactococci toward the casein fractions plays an important role in formation the parameters of quality of fermented dairy products, as well as in the creation of natural origin bioactive casein peptides. Existing methods of establishing the specificity of these enzymes are based on long-term cultivation of lactococci in milk or complex obtaining and identification of cell-envelop proteases. The aim of our study was to determine the specificity of the proteinase of lactococci using a homogeneous casein fractions as substrate. Casein fractions (αS1-, β- and κ-caseins) were isolated using differential precipitation in isoelectric point in the presence of urea and preparative electrophoresis in polyacrylamide gel. To determine the total proteolytic activity and selection of proteinase-positive strains was held their short-term cultivation (12 hours) in sterile skim milk at 30 °С. In case of development of proteinase-positive strains the concentration of proteolysis product after 12 hours of cultivation remains the same or increases. It depends on the activity and amount of the cell-envelop proteinase. It was also tested the ability of strains to form lactic acid and coagulate casein milk. These characteristics are the most important in lactic acid bacteria and are closely related to proteolytic activity. For the proteolysis protease-positive strains of lactococci, which were grown in the milk culture medium, were used. Cells were washed from the components of the culture medium and concentrated in condition while preserving their cell-envelop proteases. The specificity of cell-envelop proteases was established on the basis of electrophoretic analysis of undigestive casein substrates in alkaline system of homogeneous polyacrylamide gel. As a result of analysis of cell-envelop proteases types of four strains was defined. The proposed method can significantly reduce the time of the analysis and to identify the type and specificity of cell-envelop proteases of lactococci.
Authors and Affiliations
A. V. Iukalo, O. I. Tsisaryk
Keywords
Related Articles
- EP ID EP348287
- DOI -
- Views 91
- Downloads 0
Effect of 5-day exposure of vitamin A and E on status of red blood cell antioxidant system and hematological parameters of rats intoxicated by chlorpyrifos
The paper is dedicated to the investigation of effects of a single oral administration of chlorpyrifos, a common organophosphate pesticide, at a dose of 90 mg/kg, on the number of blood cells in peripheral blood, red blo...
Analysis of activity of existent antimicrobial preparations on markets of Ukraine
In the article the results of researches of test neat cultures sensitiveness to the wide spectrum of antimicrobial preparations are expounded with the purpose of their activity determination. The analysis of activity of...
Distribution of genetic-modified plants and safety of their use in the food and agricultural industry
This review analyzes the distribution of biotech crops in the world over the past 22 years. It is shown that there is a steady tendency to increase the areas on which genetically modified varieties of plants are grown. T...
Influence of typological features of autonomous tone on morphometric parameters of goblet cells of chickens’ intestinal mucosa
In adult chickens cross “Iza-Braun”, which were grown in conditions of poultry farms and were selected on the basis of analogues, there are two types of autonomous tone: sympathotonic (CT) — 16 specimen and sympatho-norm...
The application of the RAPD-PCR method for identification of lactic acid bacteria
The heterogeneous properties of lactic acid bacteria (LAB) create a significant difficulties in their identification. The use of genotypic methods based on polymerase chain reaction (PCR) has opened new possibilities for...