Ligase 18331 225584416 2008-07-14T12:40:02Z CarinaT 3636119 iw In [[biochemistry]], a '''ligase''' (from the [[Latin language|Latin]] verb ''ligāre'' — "to bind" or "to glue together") is an [[enzyme]] that can catalyse the joining of the sugar phosphate backbones of [[Okazaki fragments]] of DNA. Generally ligase catalyses the following reaction: :Ab + C → A–C + b or sometimes :Ab + cD → A–D + b + c where the lower case letters signify the small, pendant groups. ==Nomenclature== The common names of ligase enzymes often include the word "ligase", such as [[DNA ligase]], an enzyme commonly used in molecular biology [[laboratory|laboratories]] to join together [[DNA]] fragments. Other common names for ligases include '''synthetase''', because they are used to [[synthesis|synthesize]] new molecules, or '''carboxylase''' when they are used to add [[carbon dioxide]] to a molecule. Note that "synthetase" should not be confused with [[synthase]]s, as synthases do not use energy from [[nucleoside triphosphate]]s (such as [[Adenosine triphosphate|ATP]], [[Guanosine triphosphate|GTP]], [[Cytidine triphosphate|CTP]], [[Thymidine triphosphate|TTP]] and [[Uridine triphosphate|UTP]]) and belong to the [[lyase]] group, while ligases do use [[nucleoside triphosphate]]s. ==Classification== Ligases are classified as '''EC 6''' in the [[EC number]] classification of enzymes. Ligases can be further classified into six subclasses: *[[:Category:EC 6.1|EC 6.1]] includes ligases used to form carbon-oxygen bonds *[[:Category:EC 6.2|EC 6.2]] includes ligases used to form carbon-sulfur bonds *[[:Category:EC 6.3|EC 6.3]] includes ligases used to form carbon-nitrogen bonds (including [[argininosuccinate synthetase]]) *[[:Category:EC 6.4|EC 6.4]] includes ligases used to form carbon-carbon bonds *[[:Category:EC 6.5|EC 6.5]] includes ligases used to form [[phosphoric ester]] bonds *[[:Category:EC 6.6|EC 6.6]] includes ligases used to form nitrogen-metal bonds ==See also== *[[DNA ligase]] ==References== * [http://www.chem.qmul.ac.uk/iubmb/enzyme/EC6/intro.html EC 6 Introduction] from the Department of Chemistry at [[Queen Mary, University of London]] {{Enzymes}} {{Ligases}} [[Category:Ligases]] [[da:Ligase]] [[de:Ligase]] [[es:Ligasa]] [[fr:Ligase]] [[it:Ligasi]] [[he:ליגאז]] [[lt:Ligazės]] [[ja:リガーゼ]] [[pl:Ligazy]] [[pt:Ligase]] [[ru:Лигаза]] [[sv:Ligaser]] [[ur:پیوستگی]] [[zh:連接酶]]