HPLC analysis of neurophysin proteins from neurosecretory granules

Neurosecretory granules were obtained from neurolobes of porcine pituitary glands. From the granules, highly purified neurophysins were prepared by HPLC. According to polyacrylamide gel electrophoresis, isoelectric focusing, N- and C-terminal amino acid residue determination, and amino acid composition, the neurophysins, I1, I2, and II were identical to the neurophysins obtained from whole posterior lobes. Since degradation could not have occurred, we conclude that neurophysin I1 and I2 originated in the neurosecretory granules.