| Summary: | 碩士 === 國立中央大學 === 生命科學研究所 === 89 === Abstract
Proteomics is a systematic analysis of the proteins expressed by a cell or tissue. The combination of two-dimensional electrophoresis for protein separation with mass spectrometry for protein identification is the essential analytical tools by proteomics approach. Pseudomonas putida SH1 was capable to catabolize naphthalene, phenol or o-cresol as sole source of carbon and energy. The protein spots in 2-D gel showed that different profile induced in P. putida SH1 during growth in naphthalene, phenol or o-cresol as sole carbon source compared to using succinate as a control. Protein spots were digested by trypsin and the peptide mass fingerprints were analyzed by matrix assisted laser desorption ionization—time of flight (MALDI-TOF) mass spectrometry. Ten and five enzymes were identified to be involved in the degradation pathways of naphthalene and phenol/o-cresol, respectively. The degradation pathway of individual aromatic compound can then be constructed. The results indicated that the degradation of phenol and o-cresol may shared the same catalytic pathway in this bacterium. In addition, a general bacterial stress protein, alkyl hydroperoxide reductase (AhpC), was induced by P. putida SH1 in the medium containing individual aromatic carbon source. This is the first observation of the involvement of an AhpC protein in the stress response to aromatic compound degradation.
In the western blot analysis of 2D-gel, an aromatic ring cleavage enzyme, catechol 2,3-dioxygenase, was detected by using a polyclonal antibody against this protein. The enzyme also showed different in both molecular weight and pI in the proteome of naphthalene-grown strain SH1 and that from phenol (or o-cresol).
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