A new method of coupling [8-lysine] vasopressin to agarose: The purification of neurophysins by affinity chromatography

Abstract [8-Lysine]vasopressin was coupled to agarose through the e-amino group of the lysine residue, acetone being used to protect the α-amino group during the coupling procedure. Acetone was then removed, and the resulting derivative was used to extract neurophysins from crude neurohypophysial extracts by affinity chromatography. Neurophysins bound to the column at pH 5.8 and could then be eluted by making the eluant either more acid or alkaline. Some residual binding of neurophysin occurred under acid conditions. By this technique, one major guinea-pig neurophysin and a fourth minor porcine neurophysin were identified. Using an automated recycling method, porcine neurophysins were prepared on a large scale from dialysed extracts of posterior pituitary powder. The method is efficient and simple to perform. It has several advantages over methods in current use.