ABSTRACT
Proteins and/or enzymes are the nal products of gene expression. Although DNA stores the genetic information, it is the proteins that determine the shape and structure of a cell, a tissue, an organ, and the intact organism. Enzymes, which are usually proteins in nature, control the expression of genes and the development of an organism. Overall, proteins constitute half of the dry weight of the cell. In recent years, proteins and enzymes have become one of the core parts of molecular biology studies. Protein identi cation is important not only for detecting novel proteins, but also for monitoring protein expression in genetically modi ed animal models and/or after gene or cell transfer. A number of molecular biology studies start with the identi cation of a novel gene or protein(s) and then determine how the function or particular phenotype of an organism responds to changes in its expression. These types of experiments often utilize genetic screening of cDNA libraries followed by the cloning of a speci c gene and then bacterial and eukaryotic expression systems to identify and characterize the associated protein(s) of interest. In addition, proteins/enzymes are involved in broad molecular biology studies such as the interaction between the cis-element and the transfactor, DNA/protein interaction in gel retardation and footprinting, screening of cDNA libraries as probes, immunoblotting or precipitation, and in vitro translation.1-6
In the study of proteins and enzymes, the extraction and puri cation of these macromolecules are fundamentally important.1,7,8 The present chapter provides detailed procedures for the extraction and puri cation of protein from isolated tissues and organs.
