A radiochemical assay for N-acetyl-L-aspartate amidohydrolase (EC 3.5.1.15) and its occurrence in the tissues of the chicken

A simple and rapid radiochemical method for the determination of N-acetyl-L-aspartic acid amidohydrolase (EC 3.5.1.15) activity using ion exchange chromatography has been developed. The activity of this enzyme in the developing brain and some non-nervous tissues of the chicken has been determined. No activity of the enzyme could be detected in the brains of chick embroys prior to 14 days of gestation; activities gradually increased thereafter to adult levels which are about 60% of that found in the adult rat. In non-nervous system tissues of the adult chicken, activities varied from high levels in the kidney to low levels in heart and breast muscle. Treatment of the homogenates of the adult tissues with a detergent significantly increased the enzyme activity, suggesting that a portion of the enzyme is membrane bound.