Dear Careina, Following on from what Herman said, if you have a structure you can use the propKa server
http://propka.ki.ku.dk/ to predict pKas for amino acids in the local environment as found in your structure. Perhaps some of the propKa literature might also be helpful? HTH, Dave [image: David Briggs on about.me] David Briggs about.me/david_briggs <http://about.me/david_briggs> On 13 August 2014 12:40, Careina Edgooms < 000002531c126adf-dmarc-requ...@jiscmail.ac.uk> wrote: > Sorry for off topic question, just wondering if anyone has come across a > study that shows the residue pka of certain amino acids is different in > vitro compared to in vivo? > > Best > Careina >