Changes

<p><span style="font-size:14px">Proteomics&nbsp;is the large-scale study of proteins,&nbsp;particularly their structures&nbsp;and fucntions.&nbsp;Proteins are vital parts of living organisms, as they are the main components of the physiological metabolic pathways&nbsp;of cells.&nbsp;The term&nbsp;proteomics&nbsp;was first coined in 1997<span style="font-size:10.8333px; line-height:17.3333px">&nbsp;</span>to make an analogy with genomics,&nbsp;the study of the genome.&nbsp;The word&nbsp;proteome&nbsp;is a portmanteau&nbsp;of&nbsp;protein and genome.</span></p>

<p><span style="font-size:14px"><u>## Analysis ##</u></span></p> <p><span style="font-size:14px">1) <strong>Protein detection with antibodies (immunoassays)</strong></span></p> <p><span style="font-size:14px">Antibodies&nbsp;to particular proteins or to their modified forms have been used in biochemistry&nbsp;and cell biology&nbsp;studies. These are among the most common tools used by molecular biologists today. There are several specific techniques and protocols that use antibodies for protein detection. The enzyme-linked immunosorbent assay&nbsp;(ELISA) has been used for decades to detect and quantitatively measure proteins in samples. The Western blot&nbsp;can be used for detection and quantification of individual proteins, where in an initial step a complex protein mixture is separated using SDS-PAGE&nbsp;and then the protein of interested identified using an antibody.&nbsp;Modified proteins can be studied by developing an antibody&nbsp;specific to that modification. For example, there are antibodies that only recognize certain proteins when they are tyrosine-phosphorylated,&nbsp;known as phospho-specific antibodies. Also, there are antibodies specific to other modifications. These can be used to determine the set of proteins that have undergone the modification of interest.</span></p> <p>2) <strong>Antibody-free protein detection</strong></p> <p>While protein detection with antibodies are still very common in molecular biology, also other methods have been developed that do not rely on an antibody. These methods offer various advantages, for instance they are often able to determine the sequence of a protein or peptide, they may have higher throughput than antibody-based and they sometimes can identify and quantify proteins for which no antibody exists.</p> <p><span style="font-size:14px"><strong>Detection methods</strong></span></p> <p><span style="font-size:14px">One of the earliest method for protein analysis has been Edman degradation&nbsp;where a single peptide&nbsp;is subjected to multiple steps of chemical degradation to resolve its sequence. These methods have mostly been supplanted by technologies that offer higher throughput.&nbsp;More recent methods use mass spectrometry-based techniques, a development that was made possible by the discovery of &quot;soft ionization&quot; methods such as matrix-assisted laser desorption/ionization (MALDI)&nbsp;and electrospray ionization (ESI)&nbsp;developed in the 1980s. These methods gave rise to the top-down&nbsp;and the botton-up&nbsp;proteomics workflows where often additional separation is performed before analysis.</span></p> <h4><span style="font-size:14px"><strong>Seperation methods</strong></span></h4> <p><span style="font-size:14px">For the analysis of complex biological samples, a reduction of sample complexity is required. This can be performed off-line by one-dimensional&nbsp;or two-dimensional&nbsp;separation. More recently, on-line methods have been developed where individual peptides (in bottom-up proteomics approaches) are separated using Reversed-phase chromatography&nbsp;and then directly ionized using ESI;&nbsp;the direct coupling of separation and analysis explains the term on-line&nbsp;analysis.</span></p> <h3>&nbsp;</h3>