In the 1950s, Christian Anfinsen demonstrated the renaturation of the protein ribonuclease (RNase) in vitro. After reduction (to
reduce the disulfide links) and the addition of urea (to denature the protein), the protein was in an unfolded state. After removing the urea and the reducing agent, the protein refolded, with greater than 90% activity. If the urea were removed after oxidation occurred, the protein had less than 5% activity. Why would the protein not refold correctly if the urea were removed after the reducing agent was removed? (In other words, what would happen if the urea were removed after oxidation?) Choose the best answer. a. Urea would participate in weak bonding interactions with RNase, preventing oxidation of Cys.
b. The protein would not fully unfold (denature).
c. Disulfide bonds are not positioned correctly unless weak bonding interactions are present.
d. Contaminants in the RNase preparation would form covalent bonds with the protein, preventing reactivation.
If the area is removed, weak interactions position the -SH to form disulfide bridges, thereby enabling the oxidation. Moreover, if oxidation takes place before the urea is removed, the cysteines may be incorrectly positioned, giving rise to a dysfunctional/inactive protein.
It is the main organ that regulates nutrients and sugar flow in the blood. That is why diabetes and other diseases most commonly occur in the pancreas.
They are part of the cell's core transcription toolkit, needed for the transcription of any gene. RNA polymerase binds to a promoter with help from a set of proteins called general transcription factors.
