Plantas como biorreatores : recuperação e purificação de aprotinina recombinante a partir de semente de milho transgenico

AUTOR(ES)
DATA DE PUBLICAÇÃO

2002

RESUMO

Expression in transgenic plants is potentially one of the most economical systems for large-scale production of valuable peptide and protein products. Advantages of the use of plants as bioreactors include the low cost of growing a large amount of biomass, easy scale-up (increase of plant acreage), natural storage organs (seeds and tubers), and the reduced risk on propagating human or animal pathogens. However, the downstream processing of recombinant proteins produced in plants has not been extensively studied. In this work, we studied the extraction and purification of recombinant aprotinin, a protease inhibitor used as a therapeutic compound, produced in transgenic com seed. More than just studing the recovery and purification of a recombinant protein, the aim of this work was to add new information about the use of transgenic com as bioreactor. Conditions for extraction from transgenic com meal that maximize aprotinin concentration and its fraction of the total soluble protein in the extract were determined as pH 3.0 and 200 mM NaCI. Aprotinin in this extract, together with a native com trypsin inhibitor (CTI) was captured using a trypsin-agarose column. These two inhibitors were separated by using two different approaches: immobilized metal ion affinity chromatography IMAC (agarose-IDA-Cu2+ resin) and cation-exchange chromatography (SP Sepharose resin). The high purity of the recombinant aprotinin was verified by SDSPAGE and N-terminal sequencing. Reverse phase HPLC analysis of the recombinant aprotinin purified by IMAC suggested a purity as greater as 97%. Since CTI was also purified, the recovery and purification process studied has the advantage of possible CTI coproduction. Finally, the work presented here introduces additional information on the recovery and purification of recombinant proteins produced in plants and corroborates with past research on the potential use of plants as bioreactors

ASSUNTO(S)

engenharia bioquimica inibidores enzimaticos proteinas - separação inibidores da tripsina plantas transgenicas biotecnologia

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