Sciencemadness Discussion Board

protein pKa determination

RfoG3282 - 16-5-2013 at 21:45

Hello!
I am trying to determine the pKa of hemoglobin using UV/Vis spectrophotometry and a pH meter. I've found that I can do this by recording the changes in the spectra. I've found that I can get the pKa with a modified Henderson-Hasselbach equation but I can't quite get the math to work out. Can anyone with knowledge of the subject tell me how I should go about this?

Thanks!!

Hockeydemon - 29-5-2013 at 23:40

Quote: Originally posted by RfoG3282  
Hello!
I am trying to determine the pKa of hemoglobin using UV/Vis spectrophotometry and a pH meter. I've found that I can do this by recording the changes in the spectra. I've found that I can get the pKa with a modified Henderson-Hasselbach equation but I can't quite get the math to work out. Can anyone with knowledge of the subject tell me how I should go about this?

Thanks!!


Can you post the figures your using? When you say a modified version of the H-H equation are you referring to an actual variation or just the rearrangement to solve for pKa?

Hemoglobin K = 1.4 x 10-8; pKa = 7.85

Without knowing your figures though I'm (personally) unable to help you.