BNP (1-21), Pro (Human) is a peptide containg 21 amino acids. B-Type Natriuretic Peptide (BNP), a cardiac natriuretic hormone. BNP together with the highly homologous atrial natriuretic peptide, it forms a dual natriuretic peptide system of the heart. BNP is responsible for changes in the heart organogenesis and is associated with transition to extrauterine life.