I can understand how proteins can unfold at high temperature (high temperature = high energy = more vibrations = unfolding). But recently I was told that proteins can unfold too at low temperature? How can this happen? Is there any specific type of bond that is unstable at low temperature?
Please enlighten me. THanks
They don’t unfold, not literally, not into straight lines. If they did, black people’s hair would look like porcupines, in the Poles. That would have been in the Discovery channel, right?
But they don’t work correctly at low temperatures, for several reasons, among them:
although they are wonderful cathalysts (sp? sorry, I learned chemistry in Spanish), there is still an activation energy involved. Lower temperatures means less molecules with the right amount of energy.
proteins aren’t rigid. Their “breathing” is usually necessary for their reactions to work: when the protein “opens”, the reagents get in, then it “closes”, the reaction happens, and the products are expelled when the protein opens again. At lower temperatures, there’s less movement, including less breathing. (And yes, breathing is the technical term).
a very important force keeping proteins in the right conformation (the right folding of the pochillion possible ones) is hydrophobicity/hydrophylia. That changes with temperature, even before water freezes; if a protein needs to have a pocket of water in a certain position and the water decides to move to greener pastures, the protein isn’t in the right position any more (ok, so this terminology is not technical, but it’s more expressive than the equations and I can’t give you a drawing here)