An Improved DEAE-Cellulose Filter Assay for Colchicine Binding Protein (During Mouse Brain Development)

A DEAE-cellulose filter assay for colchicine binding protein (CBP) has been modified to include 1 m -sucrose in the incubation medium (single-point assay). Due to the much greater stability of colchicine binding capacity under the conditions described, multiple time-point assays (time-decay method) were not necessary for accurate determination of CBP in brain samples, as shown by the agreement of results obtained using the two methods to measure CBP in C129F₁ hybrid mouse brains at different stages of development. In this study, the highest concentrations of CBP (millimoles of colchicine bound per milligram of total protein) were observed in the 160,000g supernatant and pellet of newborn-brain homogenate. The CBP concentrations in these two fractions were approximately twice those observed in the earliest stage measured (13.5 days gestation) and in the 11-month-old adult. However, CBP concentration, in terms of millimoles of colchicine bound per gram of brain wet weight, reached a maximum at the end of the 1st week after birth. Between 17.5 days gestation and the end of the 1st postnatal week, more CBP accumulated in the pellet fraction than in the supernatant. Tse C. and Doherty R. A. An improved DEAE-cellulose filter assay for colchicine binding protein (during mouse brain development). J. Neurochem. 35, 767–774 (1980).