# Comparing pKa of Alpha and Beta Amino Acids

The $$\mathrm{p}K_{\mathrm{a}}$$ of the functional groups in L-glutamic acid (shown below on the right) from left to right are $$4.1$$, $$9.5$$, and $$2.1$$. Predict the $$\mathrm{p}K_{\mathrm{a}}$$ values of B-glutamic acid (below on the left).

I am not sure on the answer and I am just guessing here.

The $$\mathrm{p}K_{\mathrm{a}}$$ value for the $$\ce{COOH}$$ group on the right will increase at it won't be stabilised by the amino group any more. The $$\mathrm{p}K_{\mathrm{a}}$$ of the $$\ce{COOH}$$ on the left won't really change.I am guessing that the $$\mathrm{p}K_{\mathrm{a}}$$ of the amino group will decrease. That is a complete guess.

Can anyone please explain how exactly the amino group effects the stability of the $$\ce{COO-}$$ group and also how the $$\ce{COOH}$$ group effects the stability of the $$\ce{NH3+}$$ group.