So if you have the amino acid Lysine (basic) and you're titrating it with OH-, then why is pka1=10.5 and pka2=9 and pka3=2.2. SHouldn't it be the other way around where pka1=2.2, etc.?
couple things that are ringing some red flags. first off, as far as i remember, when you're doing titrations, you want to use a buffer, which is a weak acid or base with its corresponding conjugate pair. OH- is an extremely STRONG base and i have never seen it being used as a titrant. i may be wrong so you might want to double check this. also, if you want to neutralize lysine, which you're right is indeed a very strong basic amino acid, wouldn't you want to use an acid for the titration? (instead of using another strong base, hydroxide ion) now, if you were using an acid to titrate lysine, the 1st pka should be relatively high, since the solution is already basic. as you add more equivalents of acid then, the other corresponding pka's of lysine should decrease. if anyone else can shed some light on this, feel free to. hope i've been of some help and please forgive me if i have made any mistakes in my response. take care.
