Enables isoleucine-tRNA ligase activity. Involved in isoleucyl-tRNA aminoacylation. Part of aminoacyl-tRNA synthetase multienzyme complex. Is expressed in several structures, including alimentary system; nervous system; respiratory system; sensory organ; and urinary system. Orthologous to human IARS1 (isoleucyl-tRNA synthetase 1). [provided by Alliance of Genome Resources, Apr 2022]