Reinigung der Phosphorylase aus Kartoffeln

Purification of Phosphorylase from Potatoes. Phosphorylase (α‐1.4‐glucane: orthophosphate glucosyl transferase E.C.2.4.1.1.) was isolated from potatoes by means of five purification steps with 40 % yield in a concentration of 87 times as strong as the original one with a specific activity of 7.0 E/mg protein. By adding Na2S2O4 and by inactivation of the phenoloxidases by means of NaCN the melanine formation during the purification process was made impossible. α‐Amylase, which is especially irritating with examinations of phosphorolytic degradation was separated by a heat step (50 min, 56 °C, pH 7.0). The phenoloxidases were separated by means of ion‐exchanger chromatography with DEAE‐cellulose (0.1 M KCl). The colourless enzyme, which remains stable for months at 0–5 °C is constant in its molecular weight according to tests with gel‐ permeation‐chromatography (Sephadex G‐200) and in the ultra centrifuge. In the gel‐electrophosphoresis the enzyme moves as a uniform peak.