Identification of Parvalbumin Alpha in Bovine Hypothalamus: A Partial Primary Structure

In the course of the study of structure-functional properties and molecular mechanisms of neuropeptides and of low molecular weight proteins of the central nervous system we succeeded in isolating from the soluble fraction of bovine hypothalamus a protein having Mr 11897.3, according to mass spectral analysis. The purification procedure was mainly based on reversed phase HPLC. As the N-terminus of the molecule was found to be blocked, we have subjected it to CNBr degradation. By Edman microsequence analysis of the peptide fragments and by data base searching the isolated substance was identified as parvalbumin alpha (PRVA)—one of the calcium-binding proteins. However, its primary structure was found not to be identical to that of the known PRVAs from other sources. One of the features of PRVA is its stability. Being subjected to an exhausting purification procedure it retains its complete structure. As neuropeptides and low molecular weight proteins are found to be polyfunctional, a central question concerns the biological role of PRVAs in terms of “where and when” they express their action.