Dissolved oxygen level directly affects the synthesis of arginine by Corynebacterium crenatum(C.crenatum).Proteomic approaches including twodimensional electrophoresis(2DE)and matrixassisted laserdesorption/ionization timeofflight mass spectrometry(MALDITOFMS)were used to analyze differential expression of proteins in C.crenatum in different oxygen supply conditions.The results showed that most of the isoelectric points of the proteins on the 2DE gels distributed from 4 to 7.Thirtytwo different protein points were detected in the pH 4—7 gels and characterized by MALDITOFMS as well as peptide mass fingerprintings.Using matrixscience database

29 protein points were identified

and they represented 27 proteins.Database research showed that the proteins performed different functions in carbohydrate metabolism

amino acid metabolism and energy metabolism.Most of the differentially expressed proteins concentrated in the pentose phosphate pathway

TCA cycle and the urea cycle.The results showed that in the high oxygen supply model

energy metabolism was significantly increased

and the oxidative stress was balanced because of the increase of pentose phosphate pathway.Meanwhile

the activation of TCA cycle and urea cycle were beneficial to the synthesis of arginine.