Wheat gliadin is an ethanol-soluble fraction of wheat protein. It has several intramolecular disulfide bonds, which are cleavable by reductants such as 2-mercaptoethanol. We added 2-mercaptoethanol into the dope solution prepared by dissolving wheat gliadin in DMSO. The dope solution was spun into an acetone/methanol coagulation bath. The viscosity of the dope solution was increased and the spinnability was also improved by the addition of 2-mercaptoethanol. A maximum draw ratio of 3.5 was achieved with the addition of 2-mercaptoethanol whereas, that of non-added fiber was only 2. Furthermore, the mechanical properties of the fiber were slightly improved by the addition of 2-mercaptoethanol. These positive effects are due to the increase of chain entanglement by the cleavage of intramolecular disulfide bonds.