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영어

Transgenic plant cell cultures are an attractive expression system for the production of industrial and pharmaceutical proteins because of their advantages in safety and low production cost. Human cytotoxic T-lymphocyte antigen 4-immunoglobulin (hCTLA4Ig) was produced and secreted when sugar was depleted in culture medium by transgenic plant cell lines (Oryza sativa L.) using RAmy3D promoter. Successful production of proteins in bioreactor requires sufficient oxygen transfer into the culture medium. However, shear damage by agitation and aeration in induction phase causes cell lysis and consequently lowers productivity. Culture fluid after the beginning of cell lysis contains diverse endogenous enzymes, such as proteases and nucleases, which are capable of degrading the secreted proteins in the culture medium. In this study, to identify the types of secreted proteases, various protease inhibitors such as AEBSF, bestatin, E-64, 1,10- phenanthroline, pepstatin A and protease inhibitor cocktail were tested under the same conditions. Effects of protease inhibitors at diverse corresponding concentrations were confirmed by comparing the levels of target protein, degree of protein degradation and protease activity.