DTT is another reagent with the ability to reduce sulfidryl bridges. But I don't understand why you want to replace it if you have it in your lab. Why not use it? Even if you don't have it, it's worth buying it and do things according to protocol. It's useful for other applications

Tilahun Rabuma Diriba You can try DTT. I think its not necessary to use beta mercaptoethanol in extraction procedure but your protocol may be different.

DTT is the most common alternative of beta-mercaptoethanol.