che·mo·tax·on·o·my 
(kē′mō-tăk-sŏnə-mē, kĕm′ō-)
(kē′mō-tăk-sŏnə-mē, kĕm′ō-)n.
The classification of organisms based on differences at the biochemical level, as in the amino acid sequences of common proteins.
che′mo·tax′o·nomic (-tăk′sə-nŏmĭk) adj.
che′mo·tax′o·nomi·cal·ly adv.
che′mo·tax·ono·mist n.