Purification of Neurophysins by Affinity Chromatography

Publisher Website
Google Scholar
Abstract
(8‐Lysine)‐vasopressin was coupled to activated Sepharose by cyanogen bromide with 65%, yield. Lysine‐vasopressin antibodies were specifically retained on a lysine‐vasopressin Sepharose column and purified in a single step. They kept their ability to bind lysine‐vasopressin.Pig neurophysins prepared from fresh porcine posterior pituitaries by 0.1 M HCOOH extraction and by Sephadex gel filtration, were applied to the lysine‐vasopressin‐Sepharose column. A major protein peak was retained and eluted by 0.1 M HCOOH. Polyacrylamide gel electrophoresis of this peak revealed two major protein bands and six minor bands. These proteins have been called neurophysins for several reasons: (1) they bind lysine‐vasopressin coupled to Sepharose, (2) they show no defined absorption at 275—300 nm, (3) they have a molecular weight on dodecylsulfate‐polyacrylamide gel electrophoresis of 11 000 and 15500 which is close to those already reported for neurophysins I and II, (4) the whole amino‐acid composition is similar to that already given for the purified neurophysins. This study demonstrates the usefulness of affinity chromatography for the purification of lysine‐vasopressin‐binding proteins. It shows the heterogeneity of porcine neurophysins.