BONY FISH NEUROPHYSINS - IDENTIFICATION OF MSEL-NEUROPHYSIN AND VLDV-NEUROPHYSIN OF THE POLLACK (POLLACHIUS-VIRENS)

The two types of neurophysins known in vertebrate species, namely MSEL -neurophysin (vasopressin-like hormone-associated neurophysin) and VLD V-neurophysin (oxytocin-like hormone-associated neurophysin) have been purified from the pollack (Pollachius virens) pituitary through a com bination of molecular sieving and high-pressure liquid chromatography (HPLC). Homogeneity has been checked by gel electrophoresis and rerun in HPLC. The apparent molecular masses measured by SDS-electrophoresis are near 12 kDa, significantly higher than those found for their mamm alian homologues (10 kDa), The two types of neurophysins have been rec ognized through their N-terminal amino acid sequences. The primary str ucture of MSEL-neurophysin has been partially determined using automat ed Edman degradation applied on native and reduced-alkylated protein, as well as peptides derived by trypsin or staphylococcal proteinase hy drolyses. Comparison of pollack MSEL-neurophysin with ox, goose and fr og counterparts reveals that particular positions in the polypeptide c hain are subjected to substitutions and that the numbers of substituti ons do not seem closely related to the paleontological times of diverg ence between the different vertebrate classes. (C) Munksgaard 1994.