Natural pH gradients formed by two and three aminoacids on polyacrylamide gel: Changes of pH, segmental voltages and aminoacid distributions with time

Abstract

AbstractA natural pH gradient can be formed on polyacrylamide gel using either two (glutamic acid and lysine only) or three (glutamic acid, histidine and lysine) aminoacids as the sole carrier ampholyte species. In the two component system, glutamic acid and lysine focus as single peaks adjacent (anodically and cathodically, respectively) to the steep, linear center of the step‐function pH gradient. Histidine, in the three component system, focuses at the center of the pH gradient and separates the other two aminoacids. Each aminoacid electrofocuses at its pI. Hemoglobin electrofocuses as a sharp band in both systems and, in the two component system, remains focused at its pI for 200 h. A major conductance gap forms at the gel center in both systems with progressing time of electrofocusing; a minor and transient conductance gap develops in the glass tube just above the gel.