Progress Curve Analysis of the one stage chromogenic assay for ecarin

Influence of amino acid and N-terminal protection residue structures on peptide p-nitroanilide adsorption on polystyrene-based support

Polystyrene-based support Bio-Beads® SM-2 was employed for desalting peptide-p-nitroanilides from Oxone®. Neither tosyl, 9-fluorenyl(methoxycarbonyl), p-nitroanilide groups nor indolyl or p-hydroxyphenyl side-chains of Trp and Tyr ensured an efficient adsorption of peptide-p-nitroanilides onto Bio-Beads® SM-2. Only unsubstituted phenyl-containing protection groups (carbobenzoxy or benzoyl) and Phe residues provided the adsorption of peptides on Bio-Beads® SM-2 and their efficient desalting. This support is well suitable for multiple parallel phenyl group-containing peptide derivative separations and high-throughput screenings.

Potential Application of Recombinant Snake Prothrombin Activator Ecarin in Blood Diagnostics

We describe here the purification and cloning of a codon-optimized form of the snake prothrombin activator ecarin from the saw scaled viper (Echis carinatus) expressed in mammalian cells. Expression of recombinant ecarin (rEcarin) was carried out in human embryonic kidney cells (HEK) cells under conditions for the development and performance of a novel and scalable recombinant snake ecarin to industry standards. Clotting performance of the rEcarin was established in recalcified citrated whole blood, plasma, and fresh whole blood and found to be comparable to native ecarin (N-Ecarin). Furthermore, hemolysis was observed with N-Ecarin at relatively high doses in both recalcified citrated and fresh whole blood, while clotting was not observed with rEcarin, providing an important advantage for the recombinant form. In addition, rEcarin effectively clotted both recalcified citrated whole blood and fresh whole blood containing different anticoagulants including heparin, warfarin, dabigatran, Fondaparinux, rivaroxaban and apixaban, forming firm clots in the blood collection tubes. These results demonstrate that rEcarin efficiently clots normal blood as well as blood spiked with high concentrations of anticoagulants and has great potential as an additive to blood collection tubes to produce high quality serum for analyte analysis in diagnostic medicine.