Identification of a vitamin K-dependent carboxylase in the venom duct of a Conus snail.

T B Stanley, D W Stafford, B M Olivera, P K Bandyopadhyay

Department of Biology, University of North Carolina, Chapel Hill 27599-3280, USA.

FEBS letters 1997 Apr 21

filter terms:

Peptides from the venom ducts of cone snails (genus Conus) contain gamma-carboxyglutamate residues. The gamma-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 gamma-carboxylase recognition signal sequences and/or structural requirements at the carboxylation site.

Citation

T B Stanley, D W Stafford, B M Olivera, P K Bandyopadhyay. Identification of a vitamin K-dependent carboxylase in the venom duct of a Conus snail. FEBS letters. 1997 Apr 21;407(1):85-8