Ligase n., plural: ligases <ˈlaɪɡeɪz> Definition: enzyme that catalyzes the binding of 2 molecules

An enzyme is a catalyst or a chemical created by cells to rate up a biochemical reaction. The is usually a protein molecule through a characteristic sequence of amino acids the fold to develop a three-dimensional structure, which gives the molecule its unique properties. Another molecule through catalytic activity is ribozyme, an enzyme make of RNA rather than protein. Enzymes might be classified and named according to the reaction lock catalyze: (1) oxidoreductases, (2) transferases, (3) lyases, (4) isomerases, and (6) ligases. In essence, ligases are a team of enzymes the catalyze the binding of 2 molecules.

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Ligase Definition

What is ligase? words ‘ligase‘ come from the Latin indigenous ‘ligare‘, which method “to bind”. In biology, ligase is a course of enzyme. But, what does ligase do? let us specify ligase.

Ligase is the course of enzyme that brings about the binding or authorized of 2 molecules. That is, by meaning in biology, the course of enzyme the catalyzes the binding or joining of two macromolecules through forming brand-new bonds like C-O, C-N, and also C-S. Ligase enzyme catalyzes the ligase reaction for, e.g.

A-D + X A-X + d OR B-C + V-W B-V + c + w + f + g

Wherein d, c, w, f, g represent small pendant groups that have actually been hydrolyzed throughout the procedure of ligation or joining of two macromolecules (e.g. A-X and B-V, in the above reactions).

About 50 ligase enzymes are known and also are often referred to as “molecular glue”. DNA ligase is one example. That catalyzes the DNA fragments’ binding by developing a phosphodiester bond in between complementary ends of the DNA fragments. Thus, DNA ligase plays a critical role in repairing, replicating, and also recombination of DNA. Permit us recognize the ligase device with the assist of DNA Ligase as an example.

Ligase (biology definition): (biochemistry) one enzyme the catalyzes the binding of 2 molecules. An instance is a DNA ligase that links two fragments of DNA by creating a phosphodiester bond. Ligases room classified right into six subclasses: (1) EC 6.1 (ligases forming carbon-oxygen bonds), (2) EC 6.2 (ligases forming carbon-sulfur bonds), (3) EC 6.3 (ligases developing carbon-nitrogen bonds), (4) EC 6.4 (ligases developing carbon-carbon bonds), (5) EC 6.5 (ligases creating phosphoric ester bonds), and also (6) EC 6.6 (ligases forming nitrogen-metal bonds). Synonym: synthetase.

DNA Ligase

Definition: DNA ligases are the ligases that join or bind the two DNA fragments (also recognized as Okazaki fragments) by creating a phosphodiester bond.

Functions the DNA Ligase

DNA Ligase is essential for DNA replication as well as the DNA repairing process. DNA Ligase is widely utilized in laboratories for moving out recombinant DNA experiments. The most widely utilized ligase in a science laboratory is the DNA ligase.

READ: Ligase in hereditary Engineering

Mechanism that DNA Ligase

DNA ligase binding the 3′ hydroxyl ends of one nucleotide (or acceptor) through the 5′ phosphate finish of an additional (donor) by two covalent phosphodiester binding in the complying with steps:

In the an initial step, the DNA pieces or DNA segment or Okazaki pieces are reorganized through their energetic sites. The lysine residue that the active site that the Ligase it s okay adenylated v the addition of AMP. The release of pyrophosphate accompanies adenylation the Ligase. Ligase carry the AMP come the 5′ phosphate finish of the donor through the formation of the pyrophosphate bond. The 5′ phosphate finish of the donor is attached to the 3′ hydroxyl finish of the receptor v phosphodiester link formation.

Figure 1: DNA ligase mechanism. Credit: Sciencelearn.org.nz.

Generally, this ligases are called according to the substrate or the macromolecules connected in the reaction; for, e.g., amino acid–RNA ligase catalyzes, the C-O shortcut formation in between amino acid and transfer RNA.

Ligase enzymes are synonymous with synthetase enzymes. However, synthetase enzymes are often perplexed with synthase enzymes. Historically, synthetase enzymes were characterized as the “ligase that catalyzes the joining of two macromolecules v the utilization of the energy molecules acquired by the hydrolysis that nucleoside triphosphates (like ATP, GTP, CTP, TTP, and UTP), for example, hydrolysis that adenosine tree phosphate (ATP) molecule to adenosene diphosphate (ADP)”.

On the various other hand, synthase enzymes are the ones the catalyze the synthesis of organic macromolecules without the hydrolysis of nucleoside triphosphates.

However, later Joint commission on Biochemical Nomenclature (JCBN) announced that the term synthetase would be supplied synonymously through ligase. In ~ the very same time, ‘synthase’ would certainly be provided for the synthesis-catalyzing enzymes the may or may not involve power utilization.

There are six classes the enzymes and ligases are among them. The other classes of enzymes include oxidoreductases, transferases, hydrolases, isomerases, and lyases. Ligase and also lyase are very closely related class of enzymes. However, Ligase and lyase are various classes the enzymes.

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Table 1: Lyase Vs Ligase

Ligase Lyase
Enzymes that bring about joining or binding the two organic macromolecules Enzymes that catalyze the chemistry bond break in a biological molecule
Bond formation Bond cleavage
Ligase enzyme action via a hydrolysis reaction Lyases action by reactions other than hydrolysis and oxidation. Lyases generally act by an remove reaction
Ligase plot on 2 molecules simultaneously Lyase action on only one molecule in ~ a time
DNA replication is completed v the aid of DNA Ligase Lyases are an important part the the glycolysis and also Kreb cycle

Ligase Function

This class of enzyme plays a crucial role by joining 2 complementary macromolecules like nucleic acid. DNA ligase enzymes lug out the repairing, replication, and recombination of DNA. Ligases are one of the many widely used enzymes in the molecular biology laboratory. Ligases are provided in recombinant DNA cloning to bind annealed fragments of limit endonuclease.


Based top top the molecular bond catalyzed by the ligase enzyme, ligase can be classified into six subclasses (see Table 2).

Table 2: six subclasses that ligases

molecular bond involved Ligase subclass example
Carbon-Oxygen bonds (C-O) EC 6.1 Aminoacyl tRNA synthetase
Carbon-Sulfur binding (C-S) EC 6.2 Succinyl coenzyme A synthetase, Thiokinase
Carbon-Nitrogen bond (C-N) EC 6.3 Ubiquitin ligase, argininosuccinate synthetase
Carbon-Carbon bond (C-C) EC 6.4 Gamma-glutamyl carboxylase, Polyketide synthase
Phosphoric ester bonds EC 6.5 DNA ligase
Nitrogen-metal bonds EC 6.6 Chelatases

Note: EC stands for Enzyme Commission

Ligase Examples

Ubiquitin Ligases (C-N bond) Glutamate–cysteine ligase (C-N bond) Aminoacyl tRNA synthetase (C-O bond) Succinyl coenzyme A synthetase (C-S bond) Acetyl—CoA synthetase (C-S bond) Pyruvate carboxylase (C-C bond) Acetyl-CoA carboxylase (C-C bond) Propionyl-CoA carboxylase (C-C bond) Methylcrotonyl-CoA carboxylase (C-C bond) DNA ligase (Phosphoric ester bonds) Magnesium chelatase (Nitrogen-metal bonds) Cobalt chelatase (Nitrogen-metal bonds) DNA synthetase


Shuman S. (2009). DNA ligases: progress and also prospects. The journal of organic chemistry, 284(26), 17365–17369. Https://doi.org/10.1074/jbc.R900017200. Doherty, A. J., & Suh, S. W. (2000). Structural and mechanistic conservation in DNA ligases. Nucleic acids research, 28(21), 4051–4058. Https://doi.org/10.1093/nar/28.21.4051 Holliday, G. L., Rahman, S. A., Furnham, N., & Thornton, J. M. (2014). Trying out the biological and chemical complexity of the ligases. Newspaper of molecular biology, 426(10), 2098–2111. Https://doi.org/10.1016/j.jmb.2014.03.008