Charge-neutral proteins

The category groups proteins that have an intermediate isoelectric point (pI), and therefore tend to be roughly neutral in charge at physiological pH (7.4).

Quantitatively, proteins in this category have a charge q at physiological pH and a number of residues N such that

${\displaystyle \left| \frac{q}{\sqrt{N}} \right| < 0.25 }$

This criterion is met by roughly one-third of the proteins in Arabidopsis thaliana.