Canine Factor Xa

Canine Factor Xa (15-250 μM) and its Gla-domain truncated form (Factor Xa(-GD)) exhibit indistinguishable peptide p-nitroanilide hydrolytic activity, with nearly identical K_m and kcat values for both tested substrates^[2].
Canine Factor Xa (0.16 μM; up to 60 minutes) and its Gla-domain truncated form (Factor Xa(-GD)) exhibit indistinguishable prothrombin activation activity in solution (with or without Factor Va), but only native Canine Factor Xa shows enhanced activity in the presence of phospholipid^[2].
Canine Factor Xa retains full one-stage clotting activity when stored at 4 °C for 4.5 months in the presence of 5 mM CaCl₂, whereas activity drops to 20% of initial levels in the absence of CaCl₂^[2].
Canine Factor Xa has chymotryptic proteolysis inhibited by divalent cations (Ca²⁺, Mg²⁺), with Ca²⁺ providing near-complete inhibition at concentrations >2 mM and a half-maximal inhibitory concentration of 0.6 mM^[2].
Canine Factor Xa (5.5-55 nM) hydrolyzes a range of arginine-containing thioester substrates with highest specificity (k_cat/K_m up to 1.6 × 10⁵ M^-1s^-1) for substrates with a P₂ Gly residue, consistent with its natural prothrombin substrate^[4].
Canine Factor Xa hydrolyzes Z-Trp-Arg-NA and Z-Trp-Arg-AMC amide substrates with k_cat/K_m values around 1.0 × 10⁴ M^-1s^-1, exhibiting unusual reactivity with amides compared to other coagulation factors^[4].
Canine Factor Xa (5.5-55 nM) hydrolyzes select P'-extended thioester substrates with reduced reactivity (k_cat/K_m up to 4.5 × 10⁴ M^-1s^-1) relative to simple thioester substrates, showing a slight preference for the P₁' S-Ile analogue over S-Val^[4].

MedChemExpress (MCE) has not independently confirmed the accuracy of these methods. They are for reference only.