Hello, dear colleagues. I'm a high school student and I've got a chemistry problem. Please, can someone give me an easier explanation or a method how to calculate overall charges in hormones - oxytocin and vazopressin - according to the value of pH? I know it is connected to pKa values of each ionizable group, but I'm literally confused by the complicated structures. The pH values are 1,8; 7,4, 10,5 and 13. (I've got a table of values of pKa of all ionizable groups - alpha COOH, alpha NH3+ and the side groups, so RH or RH+...) And another thing is... What would happen to the net charge of both hormones at pH = 10,5 if there weren't the disulfide bonds? I know, presumably, that it would change the structure, but I don't know how it would affect the charges... Thank you so much.