Primary structure and functional properties of cobra (Naja naja naja) venom Kunitz-type trypsin inhibitor.
A trypsin inhibitor from the venom of the cobra Naja naja naja has been isolated by a single step of reverse-phase high-performance liquid chromatography. The protein strongly inhibits trypsin (Ki = 3.5 pM). The primary structure was determined by peptide analysis of the [14C]carboxymethylated inhibitor. The 57-residue polypeptide chain belongs to the family of Kunitz-type inhibitors, and exhibits 42% residue identity with bovine pancreatic trypsin inhibitor. The structure shows only 70% identity with the corresponding peptide from the Capa cobra (Naja nevia), establishing that the inhibitor molecule exhibits extensive variations. Functionally, a basic residue at position P3' correlates with strong inhibition.
Department of Chemistry I, Karolinska Institutet, Stockholm, Sweden.
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J
Shafqat
O U
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Beg
S J
SJ
Yin
Z H
ZH
Zaidi
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Jörnvall
D000595:Amino Acid Sequence; D000596:Amino Acids / Q000737:chemistry; D000818:Animals; D007611:Aprotinin / Q000737:chemistry* / Q000302:isolation & purification; D002851:Chromatography, High Pressure Liquid; D004546:Elapid Venoms / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D008969:Molecular Sequence Data; D012911:Snakes
D000596:Amino Acids; D004546:Elapid Venoms; D007611:Aprotinin