The amino acid sequence of the double-headed proteinase inhibitor from canine submandibular glands, III. Sequencing studies.

Canine submandibular glands contain 3 polyvalent, double-headed proteinase inhibitors. The amino acid sequences of the two main inhibitors were determined. They differ only in the substitution of one Lys for a Glu residue. The inhibitor molecules are composed of two halves (domains), one antitryptic and one antichymotryptic. The two domains are covalently linked by 3 amino acid residues. The domains are structurally related to each other and to the sequenced monovalent secretory pancreatic trypsin inhibitors.