It has been recently shown that insulin retains its biological activity after receptor-directed internalization and it may affect the cell metabolism by interaction with cytosolic insulin-binding proteins (CIBPs). Using affinity chromatography combined with SDS-PAGE and MALDI-TOF mass-spectrometry we have identified 7 proteins from mouse liver cells that specifically bind to the insulin, including adenylate kinase 2 (25.6 kD), kinesin superfamily protein 20B (26.0 kD), hepatic arginase 1 (34.8 kD), fructose-bisphosphate aldolase B (39.5 kD), 4-hydroxyphenylpyruvate dioxygenase (45.1 kD), betaine-homocysteine methyl-transferase (45.0 kD) and KRIT1 (83.4 kD).