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Identification of a vitamin K‐dependent carboxylase in the venom duct of a Conus snail
Author(s) -
Stanley Thomas B,
Stafford Darrel W,
Olivera Baldomero M,
Bandyopadhyay Pradip K
Publication year - 1997
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/s0014-5793(97)00299-8
Subject(s) - conus , biochemistry , venom , pyruvate carboxylase , enzyme , carboxylation , biology , chemistry , substrate (aquarium) , anatomy , catalysis , ecology
Peptides from the venom ducts of cone snails (genus Conus ) contain γ‐carboxyglutamate residues. The γ‐glutamyl carboxylase responsible for this post‐translational modification is localized in the microsomal fraction, strictly dependent on vitamin K, activated by ammonium sulfate, and is associated with endogenous substrate. The K m of the enzyme for vitamin K is comparable to that for the bovine carboxylase. However, a propeptide containing substrate related to the blood coagulation protein factor IX, a highly efficient substrate for the bovine enzyme, was poorly carboxylated by the Conus enzyme, suggesting differences in γ‐carboxylase recognition signal sequences and/or structural requirements at the carboxylation site.