A rapid purification of synapsin I: a neuron specific spectrin binding protein.

We have developed a one chromatographic step isolation protocol for the neuron specific protein synapsin I. This procedure results in a yield of 80 micrograms/g brain, which is ten fold better than the highest yield yet reported for this protein. The authenticity of the synapsin I isolated by this procedure is demonstrated by comigration with authentic synapsin I on SDS-polyacrylamide gels, crossreactivity with antibody specific against synapsin I, and nearly identical two dimensional chrymotryptic iodopeptide maps of authentic synapsin I and the protein purified by this protocol. Synapsin I isolated by this procedure retains its functional properties, demonstrated by the ability of synapsin I to stimulate the formation of a brain spectrin(240/235)/synapsin I/F-actin ternary complex as determined by a low shear falling ball viscometry assay. This novel protocol therefore has the advantage of being a rapid, high yield procedure that retains the functional properties of synapsin I.