Amino acid sequence of an inducible cysteine proteinase inhibitor (cystatin) from submandibular glands of isoproterenol-treated rats.
We have previously reported the purification of an inducible cysteine proteinase inhibitor from submandibular glands of isoproterenol-treated rats by sequential gel filtration and ion-exchange chromatography [G. S. Bedi (1989) Arch. Biochem. Biophys. 270, 335-343]. This inhibitor is not detected in normal rat tissues but is induced in submandibular glands following beta-adrenergic stimulation of rats. In this study the complete amino acid sequence and the position of disulfide bridges of the purified protein were determined by automated Edman degradation of the protein and its tryptic, chymotryptic, and Staphylococcus aureus V8 protease peptides and were as follows: (sequence; see text) Computer analysis revealed the presence of 40-50% sequence identity between inducible cysteine proteinase inhibitor and cystatins from human saliva, human cystatin C, bovine cystatins, and chicken cystatins, all members of Family 2 cystatins. The inhibitor has little sequence similarity with rat liver and epidermal cysteine proteinase inhibitors, which belong to Family 1 cystatins.
Department of Oral Biology, State University of New York, Buffalo 14214.
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D000595:Amino Acid Sequence; D000818:Animals; D002851:Chromatography, High Pressure Liquid; D002852:Chromatography, Ion Exchange; D002918:Chymotrypsin / Q000378:metabolism; D015891:Cystatins; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000032:analysis; D011480:Protease Inhibitors / Q000032:analysis*; D051381:Rats; D055333:Salivary Cystatins; D012471:Salivary Proteins and Peptides / Q000032:analysis*; D013363:Submandibular Gland / Q000032:analysis*; D014357:Trypsin / Q000378:metabolism
D015891:Cystatins; D010446:Peptide Fragments; D011480:Protease Inhibitors; D055333:Salivary Cystatins; D012471:Salivary Proteins and Peptides; D002918:Chymotrypsin; D014357:Trypsin