We used pH6.8 in stacking and pH8.8 in resolving gel. In the class, the professor explained that the glycine change is like:
glycine+ <-------> +glycine- <------> glycine-
it is said that most of the form will be
glycine-. Why? And why does it change the charge when it runs from the stacking gel to resolving gel? What is the role of glycine in the running buffer for SDS-polyacrylamide gel electrophoresis?