The amino-acid sequence of the double-headed proteinase inhibitor from badger (Meles meles) submandibular glands.

Abstract

Badger submandibular glands contain a double-headed secretory proteinase inhibitor. Its amino acid sequence was determined. Extensive homologies were found between this inhibitor and the corresponding inhibitors of fox, dog, lion and cat in both domains. As in fox and dog inhibitor, the trypsin-inhibiting domain of badger inhibitor contains an Arg residue in the reactive site in contrast to a Lys residue in the inhibitors of lion and cat. Domains I and II of badger inhibitor are structurally related both to the sequenced inhibitors of fox, dog, lion and cat and to the sequenced monovalent secretory pancreatic trypsin inhibitors. The sequence of the badger inhibitor is N-terminally extended by four amino acids in comparison to fox and dog inhibitors and extended by eight amino acids in comparison to lion and cat inhibitors. Furthermore, the badger inhibitor is C-terminally extended by two amino acids in comparison to the lion inhibitor and by three amino acids in comparison to all other sequenced inhibitors.