Isolation and identification of a high molecular weight brain natriuretic peptide in porcine cardiac atrium.

Brain natriuretic peptide (BNP)-like immunoreactivity has recently been shown to exist in porcine heart, although this peptide was first identified in porcine brain. A high molecular weight (MW) BNP was isolated from cardiac atrium by using anti-BNP immunoaffinity chromatography and reverse phase high performance liquid chromatography. By micorosequence analyses of the native high MW BNP as well as its tryptic and chymotryptic peptides, the complete amino acid sequence of the high MW BNP was determined. The high MW BNP consisted of 106 amino acid residues including one disulfide linkage and carried a BNP structure at its C-terminus. Since the high MW BNP was found to correspond to the gamma-form (storage form in heart) of the ANP family, this high MW BNP was designated "gamma-BNP".