Beta galactosidase is a hydrolase enzyme and it is also known as beta gal. It causes the hydrolysis of the polysaccharides that is it uses the water to break down the sugar molecules in to simpler and smaller compounds such as simple sugars. It acts on different substrates to break it down as it is a catabolic enzyme. The important substrates are lactose, lactoslyceramides, gangliosides and many other glycoproteins but lactose is an important substrate and sometimes this enzyme has been recognized by its sub class that is lactase. Beta galactosidase is actually a chemical name employed to a large group of the enzymes. Enzymes are the proteins that takes part in the catabolic activity within the cells and they act as a catalyst that is enhances and makes it faster the reaction of the hydrolysis of the molecules that would otherwise be slow and the normal physiological process can be slowed down and the life of the cells would not be possible anymore. The enzyme known as β - galactosidase is not only present in eukaryotic cells but also in prokaryotic cells. As the word indicates galatosidase, it means the breakdown of the large chain sugar lactose into smaller molecules such as glucose and galactose (Casadaban et al., 1983). Lactose is polysaccharide that is the large sugar which is formed by the combination of two smaller molecules such as glucose and galactose. In order to determine the quantity of the breakdown of lactose, one method can be adopted which is Bradford assay. In this method the Coosmassie Brilliant BlueG-250 makes bonding with a protein. This binding results in the shift in the absorption and maximum dye is thus been absorbed that is 465nm to 595 hm that is from red wavelength to blue wavelength. And thus the results are being obtained and used for the estimation of protein concentration which is then measured and compared to a standard curve (Bradford, 1976). Cell-ELISA is a very rapid and convenient technique for the quantitative detection and measurement of the concentrations of the molecules present of the cell surface. In an experiment the beta galactosidase has been used as a tag for the cell surface that is identified by the technique of ELISA (Liu et all, 2000). The reagent is responsible for protein precipitation in more prolonged time and the measurements should be completed in specific time, and this protein was identified by the technique of ELISA that is enzyme linked immuno sorbent assay and this method has been employed to identify a lot of proteins such as antibodies, antigens and their combinations and in the determination of the combination of proteins and antibodies as well as the concentration of serum antibodies such as HIV (human immuno deficiency virus), CMV (cyto megalo virus) and EBV (ebstein bar virus) tests. This technique has been used in many industries; the most important of them is the food industry in which the aim of this technique is to determine the allergen substances and their concentration in food products including dairy products such as milk, yogurt, cheese, butter etc.
This experiment has been performed in order to determine the quantity of beta glycosidase protein by the usage of the known proteins in a well defined standard curve of Bradford assay and measurement is done by obtaining the optimal titer for transformant that is E.coli and make its comparison with the non transformant one that is there by running ELISA.