The concept of an antigen and antibody pair is central to modern medicine and biotechnology. These proteins match like a lock and key, with equisite specificity. The interactions are non-covalent, but have equilibrium constants ranging from 105 to 1012 M-1 Antibodies and antigens are proteins: polypeptide chains of amino acids. The IgG antibody is composed of four polypeptide chains, two heavy and two light, organized into a ‘Y’ shape. The base of the Y is called the Fc region, while the two tips are known as the Fab region.
Traditional immunoassays such as the enzyme-linked immunosorbent assay (ELISA) are able to measure the presence or absence of only one analyte per reaction. Multiplex immunoassays measure dozens of different analytes in a single reaction. This is particularly beneficial for precious samples, and when only a small volume is collected for analysis. The multiplex immunoassay also saves working time since multiple assays can be completed simultaneously.
Immunoprecipitation (IP) is a method used to purify target proteins from whole tissue or from cell culture. There are different types of IP: Single protein, Co-immunoprecipitation (co-ip), Chromatin immunoprecipitation(CHIP), RNA immunoprecipitation (RIP), and tagged protein immunoprecipitation.
Immunoaffinity chromatography is a method for separating target antibodies or antigens from a heterogenous solution. It is column-based, which means that the solution is flowed through a column and eluted at the other end. The column is pre-functionalized with the capture antibody or antigen. The target protein is adsorbed onto the resin-bound capture protein and is retained in the column while the remaining solution is eluted. The fraction containing the target protein is later eluted and purified.
Size exclusion chromatography columns are used to separate molecules by size, molecular weight, and hydrodynamic volume. The technique can be used with proteins, polymers, and other macromolecules. It can also be used for buffer exchange or desalting a sample. The principle behind size exclusion chromatography columns is simple, but the technique only works when the correct resin-bound column is matched to the experimental goal.
Enzymes are used in the food, agricultural, cosmetic, and pharmaceutical industries to control and speed up reactions in order to quickly and accurately obtain a valuable final product. Enzymes are crucial to making cheese, brewing beer, baking bread, extracting fruit juice, tanning leather, and much more. The industrial uses of enzymes are also increasing since they are being used in the production of biofuels and biopolymers. The enzymes can be harvested from microbial sources or can be made synthetically. Yeast and E. coli are commonly engineered to overexpress an enzyme of interest. This type of enzyme engineering is a powerful way to obtain large amounts of enzyme for biocatalysis in order to replace traditional chemical processes.
Proteins are essential components of cells, tissue, and organisms. These macromolecules are made of long strings of amino acids arranged specifically into three dimensional configurations. The side chains of these 22 amino acids create pockets of potential for chemical interactions as the polypeptides fold into their tertiary structures and interact with each other. Proteins initiate and mediate the thousands of biochemical pathways that govern an organism’s function. The careful study of proteins can reveal information about the function of our bodies, the pathways of disease, and the expression of the genetic code. The main challenge to overcome when studying proteins is to choose the most appropriate method of protein extraction.
Nano gold is another name for gold nanoparticles. These nanoparticles are a fraction of the size of human hair and are less than 100 nm in diameter. Nano gold particles are so small that it they are generally found as a colloidal solution, which means that the gold nanoparticles are suspended in a liquid buffer. Therefore, nano gold, or gold nanoparticles are also called colloidal gold. Also, nano gold is generally found in a colloidal solution because gold nanoparticles are created by citrate synthesis. This process involves mixing solutions together to result in the precipitation of gold nanoparticles into solution.