Abstract: In this work the structure of fragments of alpha-human atrial natriuretic polypeptide was determined by fast atom bombardment mass spectrometry. By analysing the m/z values of the fragment ions the sequences of amino acids can be expressed clearly. In molecular area all of the ione-are [M+H]>⁺ ions. The mass of C-terminal fragment ion is exactly the fragment mass, but the mass of N-terminal fragment ion is generally equal to the mass of the fragment pit's two hydrogen atoms.

Key words: α-HANP, FAB-MS, Sequences of amino acids