title: Effect of Ca2+ and Mg2+ concentration in culture medium on the activation of recombinant factor IX produced in Chinese hamster ovary cells.
abstract: Factor IX (FIX) plays an important role in the blood coagulation cascade. When Chinese hamster ovary (CHO) cells producing recombinant human FIX were cultivated using a serum-free medium (SFM) containing 1.12 mM of Ca(2+) and 0.82 mM of Mg(2+), a significant amount of active FIX (aFIX) was converted into undesirable activated FIX (FIXa) in the later phase of batch culture. In an effort to improve aFIX production from CHO cells, the effect of Ca(2+) and Mg(2+) concentrations in the culture medium on the activation of aFIX to FIXa was investigated using SFM with various concentrations of Ca(2+) and Mg(2+) in the range of 0-1.0 mM. The highest aFIX concentration of 1.36 IU/mL was obtained at 1.0 mM Ca(2+) and 1.0 mM Mg(2+), but the activation of aFIX to FIXa in the later phase of culture was rapid and significant. In contrast, at 0.5 mM Ca(2+) and 1.0 mM Mg(2+), the aFIX concentration of 1.33 IU/mL was obtained and did not decrease significantly in the later phase of culture. Taken together, lowering Ca(2+) concentration from 1.0 to 0.5 mM inhibits the activation of aFIX to FIXa in the later phase of culture, fortifying the robustness of downstream bioprocessing.
authors.affiliation: Department of Biological Sciences, KAIST, 335 Gwahangno, Yuseong-gu, Daejeon 305-701, Republic of Korea.
authors.forename: Won Hee
authors.initials: WH
authors.lastname: Kim
authors.forename: Jung-Seob
authors.initials: JS
authors.lastname: Kim
authors.forename: Jung-Seop
authors.initials: JS
authors.lastname: Kim
authors.forename: Yeup
authors.initials: Y
authors.lastname: Yoon
authors.forename: Gyun Min
authors.initials: GM
authors.lastname: Lee
mesh_terms: D000818:Animals; D016466:CHO Cells; D002118:Calcium / Q000494:pharmacology*; D002470:Cell Survival; D006224:Cricetinae; D003412:Cricetulus; D016895:Culture Media, Serum-Free / Q000737:chemistry / Q000378:metabolism*; D004492:Edetic Acid / Q000737:chemistry; D005164:Factor IX / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D005260:Female; D008274:Magnesium / Q000494:pharmacology*; D010053:Ovary / Q000187:drug effects / Q000378:metabolism; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism
chemical_list: D016895:Culture Media, Serum-Free; D011994:Recombinant Proteins; D005164:Factor IX; D004492:Edetic Acid; D008274:Magnesium; D002118:Calcium