U rea, this small molecule has been a lifesaver in my lab work, especially when dealing with stubborn western blots for transmembrane proteins. Urea, composed of two amide groups (Figure 1), i s one of the most widely used protein denaturants in protein biochemistry. Fig 1. Chemical structure of Urea (Fun fact: if you’re looking for smoother hands, check out hand creams containing urea—it’s also a moisturizing agent!) One of urea’s favorite applications is in proteomics, where it is used to unfold and solubilize proteomes, making them susceptible to trypsin digestion. Its history in protein science goes back to Anfinsen’s famous experiment, which demonstrated that the code for protein folding reside in the amino acid sequence. Anfinsen unfolded ribonuclease using urea, and upon removing it, some proteins refolded, proving the “code” for folding is intrinsic to the sequence. Like many scientists, I’ve been using urea in my experiments for years without giving much thought to how i...