Affinity liquid‐liquid extraction of lactate dehydrogenase on a large scale

Abstract

Rapid liquid‐liquid extraction of lactate dehydrogenase from muscle by using a low‐cost aqueous bipolymer two‐phase system was achieved by using a centrifugal separator. Extraction of the target enzyme into the upper phase was enhanced by including the dye Procion yellow HE‐3G (bound to polyethylene glycol). The dye acted as an affinity ligand for the enzyme. The isolation of the enzyme was carried out either by using a cell extract or by homogenizing the muscle directly in the system. The latter approach reduced the preparation time with a factor of 0.25. The two methods gave, respectively, 310 and 360 kU lactate dehydrogenase/kg muscle (measured at 22°C). By using a small centrifugal separator, Alfa Laval LAPX 202, 3–5 kg muscle could be processed/h in a 30‐L, two‐phase system.