PH of neutrality is not exactly 7 (25 °C), although this is a good approximation in most cases. Neutrality is defined as the condition where [H] = [OH] (or the activities are equal). Since self-ionization of water holds the product of these concentration [H]×[OH] = K, it can be seen that at neutrality [H] = [OH] = , or pH = pK/2. pK is approximately 14 but depends on ionic strength and temperature, and so the pH of neutrality does also. Pure water and a solution of NaCl in pure water are both neutral, since dissociation of water produces equal numbers
6TMS neutral amino acid transporter family the Transporter Classification Database. A gene encoding a small neutral amino acid transporter was cloned from the genome of the hyperthermophilic archaeon "Thermococcus" sp. KS-1. The cloned gene, "snatA", encodes a protein of 216 amino acid residues, SnatA (TC# 2.A.95.1.4), with six membrane-spanning segments (TMSs). Competition studies indicated that SnatA transports various L-type neutral amino acids. It has also been noted that glycine transport is inhibited by a protonophore, FCCP, or valinomycin plus nigericin, indicating that the process is dependent on an electrochemical potential of H. The generalized reaction catalyzed by SnatA is:Amino acid (in) → Amino acid (out) MarC