List of EC numbers (EC 6)

List of EC numbers (EC 6) encompasses a group of enzymes categorized under EC 6, which are primarily involved in ligase activities. Ligases are enzymes that catalyze the joining of two molecules with the concomitant hydrolysis of a diphosphate bond in ATP or a similar triphosphate. This category is crucial in various biochemical pathways, including but not limited to DNA repair, replication, and the synthesis of complex molecules. The EC (Enzyme Commission) numbers are a numerical classification scheme for enzymes, based on the chemical reactions they catalyze. As a subclass, EC 6 enzymes play a pivotal role in the synthesis of key biological molecules.

Overview

Ligases (EC 6) are enzymes that facilitate the joining of two molecules by forming a new chemical bond, accompanied by the hydrolysis of a pyrophosphate bond in ATP or another nucleotide. This process is vital in numerous biological pathways, including the synthesis of nucleic acids, proteins, and other macromolecules. The EC 6 category is further divided into subclasses based on the type of bond formed or the molecules involved in the ligation process.

Subclasses

The EC 6 class of enzymes is subdivided into several subclasses, each focusing on a specific type of bond formation:

• EC 6.1 - Aminoacyl-tRNA ligases
• EC 6.2 - Acid-thiol ligases
• EC 6.3 - Carbon-nitrogen ligases
• EC 6.4 - Carbon-carbon ligases
• EC 6.5 - Carbon-oxygen ligases
• EC 6.6 - Carbon-sulfur ligases

Each subclass plays a unique role in cellular metabolism and the synthesis of critical biomolecules.

Significance

Ligases are essential for the life of the cell, participating in critical processes such as DNA synthesis and repair, protein synthesis, and the metabolic assembly of complex molecules. Their ability to catalyze the formation of new bonds using the energy derived from ATP hydrolysis is fundamental to the maintenance and propagation of life.

Examples

Some notable enzymes within the EC 6 category include:

• EC 6.1.1.1 - Aminoacyl-tRNA synthetase, which plays a critical role in protein synthesis by attaching amino acids to their respective tRNA molecules.
• EC 6.2.1.1 - Acyl-CoA synthetase, which activates fatty acids for degradation or biosynthesis.
• EC 6.3.2.1 - Glutamine synthetase, involved in the synthesis of glutamine from glutamate and ammonia.
• EC 6.4.1.1 - Pyruvate carboxylase, a key enzyme in gluconeogenesis.

Research and Applications

Understanding the function and mechanism of ligases is crucial for biotechnological and medical applications. For instance, manipulating these enzymes can lead to the development of novel antibiotics, cancer therapies, and methods for the synthesis of biologically important molecules.

See Also

• Enzyme
• Catalysis
• Biochemistry
• Metabolism

External Links

• International Union of Biochemistry and Molecular Biology (IUBMB)
• NCBI Enzyme Database