Charakterisierung der Linalool - Isomerase

Thauera linaloolentis 47LolT isomerizes linalool to geraniol. Even though the enzyme linalool-isomerase is not characterized entirely, it is assumed to be 70 kDa protein. Typically, proteins are released in a consequence of disrupting bacterial cells sonication, osmosis, lysozyme and cycle of freeze-thawing. Contrary to that mechanism the linalool-isomerase protein is not released. The enzyme activity was assessed in the soluble fraction after destroying the cells by high-pressure disruption. To gather evidence for a pontential membrane association a di erential centrifugation was performed. The enzyme activity doesn't need metal ions and it wasn't inhibited by EDTA. The enzyme activity was found in one fraction with a sedimentation coe cient of 30 Svedberg. Linalool-isomerase is estimated a very large enzyme or possibly a multiprotein complex or membrane complex. Copper ions have an inhibiting e ect. In anoxic enzyme assays 4 mmol L-1 dithionit is required as a reductant. An inhibition of linalool-isomerase activity by iodoacetic acid indicates a signi cance of cystein side chains in the enzyme catalysis. Thermodynamically linalool is stable as a geraniol, therefore the back reaction is favoured. The forward enzyme reaction reached highest transition rates with a pure linalool phase. This study is the rst one to showed provide evidence for the presence of a large protein in the cells and in the crude extract. Future puri cation attempts should take the hydrophobic nature and the size of the complex in to account