Cystatin-like domain of mouse countertrypin, a member of mammalian fetuin family, is responsible for the inhibition of trypsin. Evidence from site-directed mutagenesis.
Members of mammalian fetuin family, such as human alpha 2 HS glycoprotein and bovine fetuin, consist of three domains, two tandemly arranged cystatin-like domains and an unrelated domain, but they have no inhibitory activity against cysteine proteinases. We found that countertrypin, a novel trypsin inhibitor, is mouse counterpart of human alpha 2 HS glycoprotein, and that human alpha 2 HS glycoprotein and bovine fetuin which were prepared without use of ethanol are capable of inhibiting trypsin (Yamamoto, K. and Sinohara, H. (1993) J. Biol. Chem, 268, 17750-17753). In the present study, cDNA encoding countertrypin was isolated and sequenced, and evidence is presented, based on the site-directed mutagenesis, that lysine-231 in the second cystatin domain is the P1 site for trypsin inhibition.
Yoshida
K
K
Department of Biochemistry, Kinki University School of Medicine, Osaka, Japan.
Suzuki
Y
Y
Yamamoto
K
K
Sinohara
H
H
D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D002417:Cattle; D015891:Cystatins / Q000378:metabolism*; D018076:DNA, Complementary / Q000302:isolation & purification; D006023:Glycoproteins / Q000235:genetics* / Q000378:metabolism*; D006801:Humans; D008239:Lysine / Q000235:genetics; D051379:Mice; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D014361:Trypsin Inhibitors / Q000235:genetics / Q000378:metabolism*; D000509:alpha-Fetoproteins / Q000737:chemistry / Q000235:genetics
D015891:Cystatins; D018076:DNA, Complementary; D006023:Glycoproteins; D011994:Recombinant Proteins; D014361:Trypsin Inhibitors; D000509:alpha-Fetoproteins; C103174:countertrypin protein, mouse; D008239:Lysine