PH PH In chemistry, pH () is a logarithmic scale used to specify the acidity or basicity of an aqueous solution. It is approximately the negative of the base 10 logarithm of the molar concentration, measured in units of moles per liter, of hydrogen ions. More precisely it is the negative of the base 10 logarithm of the activity of the hydrogen ion. At 25 °C, solutions with a pH less than 7 are acidic and solutions with a pH greater than 7 are basic. The neutral value of the pH depends on the temperature, being lower than 7 if the
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