An aminoacyl-tRNA synthetase, also called tRNA-ligase, is an enzyme that attaches the appropriate amino acid onto its corresponding tRNA. It does so by catalyzing the transesterification of a specific cognate amino acid or its precursor to one of all its compatible cognate tRNAs to form an aminoacyl-tRNA. In humans, the 20 different types of aa-tRNA are made by the 20 different aminoacyl-tRNA synthetases, one for each amino acid of the genetic code.
Biosynthesis, i.e., chemical synthesis occurring in biological contexts, is a term most often referring to multi-step, enzyme-catalyzed processes where chemical substances absorbed as nutrients serve as enzyme substrates, with conversion by the living organism either into simpler or more complex products. Examples of biosynthetic pathways include those for the production of amino acids, lipid membrane components, and nucleotides, but also for the production of all classes of biological macromolecules, and of acetyl-coenzyme A, adenosine triphosphate, nicotinamide adenine dinucleotide and other key intermediate and transactional molecules needed for metabolism. Thus, in biosynthesis, any of an array of compounds, from simple to complex, are converted into other compounds, and so it includes both the catabolism and anabolism of complex molecules. Biosynthetic processes are often represented via charts of metabolic pathways. A particular biosynthetic pathway may be located within a single cellular organelle, while others involve enzymes that are located across an array of cellular organelles and structures.
In enzymology, an alanine—tRNA ligase is an enzyme that catalyzes the chemical reaction
In enzymology, an arginine—tRNA ligase is an enzyme that catalyzes the chemical reaction
In enzymology, an asparagine-tRNA ligase is an enzyme that catalyzes the chemical reaction
In enzymology, an aspartate—tRNA ligase is an enzyme that catalyzes the chemical reaction
In enzymology, a cysteine—tRNA ligase is an enzyme that catalyzes the chemical reaction
In enzymology, a glutamate—tRNA ligase is an enzyme that catalyzes the chemical reaction
Glutamine—tRNA ligase or glutaminyl-tRNA synthetase (GlnRS) is an aminoacyl-tRNA synthetase, also called tRNA-ligase. is an enzyme that attaches the amino acid glutamine onto its cognate tRNA.
In enzymology, a histidine-tRNA ligase is an enzyme that catalyzes the chemical reaction
In enzymology, an isoleucine—tRNA ligase is an enzyme that catalyzes the chemical reaction
In enzymology, a leucine—tRNA ligase is an enzyme that catalyzes the chemical reaction
In enzymology, a lysine—tRNA ligase is an enzyme that catalyzes the chemical reaction
In enzymology, a methionine—tRNA ligase is an enzyme that catalyzes the chemical reaction
In enzymology, a phenylalanine—tRNA ligase is an enzyme that catalyzes the chemical reaction
In enzymology, a proline—tRNA ligase is an enzyme that catalyzes the chemical reaction
In enzymology, a serine—tRNA ligase is an enzyme that catalyzes the chemical reaction
In enzymology, a tryptophan-tRNA ligase is an enzyme that catalyzes the chemical reaction
In enzymology, a valine—tRNA ligase is an enzyme that catalyzes the chemical reaction
Amino acid activation refers to the attachment of an amino acid to its respective transfer RNA (tRNA). The reaction occurs in the cell cytosol and consists of two steps: first, the enzyme aminoacyl tRNA synthetase catalyzes the binding of adenosine triphosphate (ATP) to a corresponding amino acid, forming a reactive aminoacyl adenylate intermediate and releasing inorganic pyrophosphate (PPi). Subsequently, aminoacyl tRNA synthetase binds the AMP-amino acid to a tRNA molecule, releasing AMP and attaching the amino acid to the tRNA. The resulting aminoacyl-tRNA is said to be charged.
