 The amino acid residues His28 and Asp26 are needed for the bioactivity of HNTX-I.HNTX-II has a molecular weight of 4253 Da and contains 37 amino acid residues.The complete amino acid sequence of HNTX-II is NH2-LFECSV SCEIEK EGNKD CKKKK CKGGW KCKFN MCVKV-COOH.