title: Partial characterization of a 230,000-dalton reticulocyte protein and peptides derived from it that affect the activity of a protein phosphatase.
abstract: Monoclonal antibodies were raised that recognize a series of highly antigenic, protease-sensitive peptides that modulate protein phosphatase activity in reticulocyte extracts. Purified antigen peptides cause a 3-fold increase in the enzymatic activity of a homogeneous Mr congruent to 56,000 protein phosphatase. The monoclonal antibodies inhibit protein phosphatase activity in crude extracts but do not recognize the protein phosphatase itself. The antigen peptides are associated with the phosphatase throughout its purification from the postribosomal supernatant of rabbit reticulocytes but are separated from it during size exclusion high performance liquid chromatography (see accompanying article: Wollny, E., Watkins, K., Kramer, G., and Hardesty, B. (1984) J. Biol. Chem. 259, 2484-2492). The series of antigenic peptides appears to be derived by proteolysis from a 230,000-Da precursor, which is relatively abundant in undegraded form in the membrane fraction of rabbit reticulocytes and is present in erythrocyte ghosts. Antigen peptides are extracted with spectrin from both sources. The Mr congruent to 230,000 peptide is not the alpha or beta subunit of spectrin or ankyrin and appears not to have been recognized previously. The name "regulin" is proposed.
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal; D000936:Antigen-Antibody Complex; D001798:Blood Proteins / Q000302:isolation & purification* / Q000502:physiology; D002846:Chromatography, Affinity; D007700:Kinetics; D008970:Molecular Weight; D010455:Peptides / Q000302:isolation & purification / Q000502:physiology; D010749:Phosphoprotein Phosphatases / Q000097:blood*; D011817:Rabbits; D012156:Reticulocytes / Q000201:enzymology*
chemical_list: D000911:Antibodies, Monoclonal; D000936:Antigen-Antibody Complex; D001798:Blood Proteins; D010455:Peptides; D010749:Phosphoprotein Phosphatases