Why do disulfide bonds require an oxidizing environment?

Faviola Dewire: 7 years later, I found that the extracellular space was an oxidizing environment. The "normal extracellular pH is 7.4" and the "Intracellular pH is around 6.8 due to acid production" (http://en.wikipedia.org/wiki/Intracellular_pH).There are more electron acceptors / molecules that would cause oxidation, in a more acidic environment . The intracellular space is more acidic. Why is the extracellular space considered the location for disulfide bond formation?...Show more

Janean Guz: well think about it.You have these S-containing amino acids. MET and CYS. In free form, these are reduced. To join them you need an environment that will rip off those H's more easily, so that the disulfide bond can form and the emerging protein can take to it's structure. That's an OXIDIZING environment....Show more