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Purification and characterization of a chymotrypsin Kunitz inhibitor type of polypeptide fro the venom of cobra ( Naja naja naja )
Author(s) -
Shafqat Jawed,
Zaidi Zafar H.,
Jörnvall Hans
Publication year - 1990
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(90)81426-o
Subject(s) - naja , venom , chemistry , chymotrypsin , protease inhibitor (pharmacology) , biochemistry , protease , trypsin , kunitz sti protease inhibitor , fast protein liquid chromatography , molecular mass , enzyme , chromatography , biology , virology , human immunodeficiency virus (hiv) , antiretroviral therapy , viral load
A chymotrypsin Kunitz inhibitor type of polypeptide has been isolated from the venom of Naja naja naja by reverse phase HPLC and cation exchange FPLC. It is present in a considerably lower amount than that of the corresponding trypsin inhibitor. The primary structure, determined by sequence analysis of the whole molecule and its tryptic peptides, has 57 residues with an apparent molecular mass of 6.2 kDa. The main contact site with the protease (P1) has a Phe, showing the specificity of the inhibitor. Of residues considered functionally important in Kunitz‐type inhibitors, Gly‐36 is replaced by Ser in a segment of weak contacts with the protease.