O→N-Acetyl Shift of O-Acetylserine and O-Acetylthreonine. An Approach to the Separation of Serine and Threonine Fraction from Amino Acid Mixture

The reaction rate of O→N-acetyl shift of O-acetylserine was compared with that of O-acetylthreonine, and it was found that the latter was greater than the former. By utilizing the difference of the rates of the reaction of these amino acid derivatives, an attempt to separate serine and threonine from their mixture was unsuccessful owing to the fact that the shift reaction was affected by many factors, i. e., the ionic strength of inorganic salts present, pH of the reaction medium and the reaction temperature. Serine and threonine were isolated from the acid hydrolyzate of casein through their O-acetylation and subsequent O→N-acetyl migration with 80∼90% yield.