In enzymology, an isoleucine—tRNA ligase () is an enzyme that catalyzes the chemical reaction
ATP + L-isoleucine + tRNAIle AMP + diphosphate + L-isoleucyl-tRNAIle
The 3 substrates of this enzyme are ATP, L-isoleucine, and tRNA(Ile), whereas its 3 products are AMP, diphosphate, and L-isoleucyl-tRNA(Ile).
This enzyme belongs to the family of ligases, to be specific those forming carbon-oxygen bonds in aminoacyl-tRNA and related compounds. The systematic name of this enzyme class is L-isoleucine:tRNAIle ligase (AMP-forming). Other names in common use include isoleucyl-tRNA synthetase, isoleucyl-transfer ribonucleate synthetase, isoleucyl-transfer RNA synthetase, isoleucine-transfer RNA ligase, isoleucine-tRNA synthetase, and isoleucine translase. This enzyme participates in valine, leucine and isoleucine biosynthesis and aminoacyl-trna biosynthesis.
Structural studies
As of late 2007, 10 structures have been solved for this class of enzymes, with PDB accession codes , , , , , , , , , and .