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In biochemistry, a binding site is a region on a protein or piece of DNA or RNA to which ligands (specific molecules and/or ions) may form a chemical bond. An equilibrium exists between unbound ligands and bound ligands. The term ''saturation'' refers to the fraction of total binding sites that are occupied at any given time. When more than one type of ligand can bind to a binding site, competition ensues. Binding sites also exhibit chemical specificity, a measure of the types of ligands that will bond, and affinity, which is a measure of the strength of the chemical bond. Binding sites are often an important component of the functional characterization of biomolecules. For example, the characterization of the binding site of a substrate to an enzyme is essential to model the reaction mechanism responsible for the chemical change from substrate to product. Binding sites on proteins can sometimes recognize other proteins. When a binding site of one protein identifies with another protein's surface, a non-covalent bond is formed between the two polypeptide (peptide) chains and a combined new protein is formed. 〔 Alberts B, Bray D, Hopkin K, Johnson AD, Lewis J, Raff M, Roberts K, Walter P. (2010) Essential Cell Biology third edition.〕 A more specific type of binding site is the transcription factor binding site present on DNA. Binding sites also exist on antibodies as specifically coded regions that bind antigens based upon their structure.〔(Binding Site - definition from Biology-Online.org )〕 == See also == * Active site * NTP binding site * DNA binding site 抄文引用元・出典: フリー百科事典『 ウィキペディア(Wikipedia)』 ■ウィキペディアで「Binding site」の詳細全文を読む スポンサード リンク
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