Many molecular biology protocols advice against sterilizing HEPES (4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid) solutions by autoclave.
Supposedly, HEPES is heat labile, and the high temperatures used for sterilization somehow impair the function of the buffer, or perhaps generate unwanted chemical species (this is speculation on my part; I've often seen the advice to not autoclave HEPES, but never seen anything about why not). Typically autoclaves heat solutions to 121C and increase pressure to slightly above 2 atm, which is about a degree short of the boiling point of water. This environment is maintained for 20 minutes in order to destroy biological contaminants.
I have seen this claim often, but had trouble locating an actual source or reasoning for why HEPES should not be autoclaved. Has there been a publication that actually tried to heat a HEPES buffer to autoclave temperatures (121C) and see what happens? What exactly is the consequence, especially with regard to the biological uses of HEPES (ie. pH buffer)?