Hey everyone, welcome back to my biochemistry blog. Today’s blog will be a brief summary about Anfinsen’s Experiment and its relationship to protein folding.

Anfinsen was a pioneer in protein folding as he wanted to  demonstrate that protein folding was entirely due to the amino acid sequence of the protein. In this experiment he treated ribonuclease with urea and β-mercaptoethanol. So let’s look at the experiment in a little more detail.The disulfide bonds in ribonuclease forms cross links between certain parts of the polypeptide and therefore the major factor that determine the shape of the ribonuclease.

figure 3-19a

 Anfinsen later realized that these bonds can be reduced in the presence of high concentrations of β-mercaptoethanol. He added urea which denatured the reduced ribonuclease lacking the disulfide bonds allowing it to form a random coil. The coil was free to form. This was because as all 8 cysteine residues were reduced and now the polypeptide was able to form any shape. In refolding he removed the reducing agent and the urea and realized that the protein folded spontaneously. Therefore his experiment was successful in proving that the shape of a protein was determined by its amino acid sequence.


As this is only a brief summary of the experiment I urge you guys to do some more research and feel free to comment below any new findings or other information that I can add. Once again thank you for viewing my blog.


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Youtube- Biochem JM

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