Blarina toxin, a mammalian lethal venom from the short-tailed shrew Blarina brevicauda: Isolation and characterization.
Venomous mammals are rare, and their venoms have not been characterized. We have purified and characterized the blarina toxin (BLTX), a lethal mammalian venom with a tissue kallikrein-like activity from the submaxillary and sublingual glands of the short-tailed shrew Blarina brevicauda. Mice administered BLTX i.p. developed irregular respiration, paralysis, and convulsions before dying. Based on the amino acid sequence of purified protein, we cloned the BLTX cDNA. It consists of a prosequence and an active form of 253 aa with a typical catalytic triad of serine proteases, with a high identity with tissue kallikreins. BLTX is an N-linked microheterogeneous glycoprotein with a unique insertion of 10 residues, L(106)TFFYKTFLG(115). BLTX converted kininogens to kinins, which may be one of the toxic pathogens, and had dilatory effects on the blood vessel walls. The acute toxicity and proteolytic activity of BLTX were strongly inhibited by aprotinin, a kallikrein inhibitor, suggesting that its toxicity is due to a kallikrein-like activity of the venom.
Kita
Masaki
M
Research Center for Materials Science, Nagoya University, Furo-cho, Chikusa, Nagoya 464-8602, Japan.
Nakamura
Yasuo
Y
Okumura
Yuushi
Y
Ohdachi
Satoshi D
SD
Oba
Yuichi
Y
Yoshikuni
Michiyasu
M
Kido
Hiroshi
H
Uemura
Daisuke
D
D000595:Amino Acid Sequence; D000818:Animals; D008969:Molecular Sequence Data; D010447:Peptide Hydrolases / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D012788:Shrews / Q000235:genetics / Q000378:metabolism*; D013361:Sublingual Gland / Q000378:metabolism; D013363:Submandibular Gland / Q000378:metabolism; D020840:Tissue Kallikreins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D014688:Venoms / Q000235:genetics / Q000378:metabolism*
D014688:Venoms; D010447:Peptide Hydrolases; D020840:Tissue Kallikreins; C487512:blarina toxin, Blarina brevicauda