How do amino acids look like at the isoelectric point?
By Henderson relation we have 

$$\mathrm{pH=pI=p}K_\mathrm{a}+\log\left(\frac{[\ce{A-}]}{[\ce{AH}]}\right)$$

So if $\mathrm{pH - p}K_\mathrm{a} &lt; 0$ then $[\ce{A-}] &lt; [\ce{AH}]$

And if $\mathrm{pH - p}K_\mathrm{a} &gt; 0$ then $[\ce{A-}] &gt; [\ce{AH}]$

If you want then to know the exact proportion you need to know the concentration of your amino-acid.