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- Characterization of Protocatechuate 4,5-Dioxygenase Induced from p-Hydroxybenzoate-Cultured Pseudomonas sp. K82
- Sung-Ho Yun , Chi-Young Yun , Seung Il Kim
- J. Microbiol. 2004;42(2):152-155.
- DOI: https://doi.org/2029 [pii]
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Abstract
- Pseudomonas sp. K82 has been reported to be an aniline-assimilating soil bacterium. However, this strain can use not only aniline as a sole carbon and energy source, but can also utilize benzoate, phydroxybenzoate, and aniline analogues. The strain accomplishes this metabolic diversity by using different aerobic pathways. Pseudomonas sp. K82, when cultured in p-hydroxybenzoate, showed extradiol cleavage activity of protocatechuate. In accordance with those findings, our study attempted the purification of protocatechuate 4,5-dioxygenase (PCD 4,5). However the purified PCD 4,5 was found to be very unstable during purification. After Q-sepharose chromatography was performed, the crude enzyme activity was augmented by a factor of approximately 4.7. From the Q-sepharose fraction which exhibited PCD 4,5 activity, two subunits of PCD4,5 ([alpha]subunit and [beta] subunit) were identified using the N-terminal amino acid sequences of 15 amino acid residues. These subunits were found to have more than 90% sequence homology with PmdA and PmdB of Comamonas testosteroni. The molecular weight of the native enzyme was estimated to be approximately 54 kDa, suggesting that PCD4,5 exists as a heterodimer ([alpha]_1[beta]_1). PCD 4,5 exhibits stringent substrate specificity for protocatechuate and its optimal activity occurs at pH 9 and 15^oC. PCR amplification of these two subunits of PCD4,5 revealed that the [alpha] subunit and [beta] subunit occurred in tandem. Our results suggest that Pseudomonas sp. K82 induced PCD 4,5 for the purpose of p-hydroxybenzoate degradation.
- Catabolism of 4-Hydroxybenzoic Acid by Pseudomonas sp. DJ-12
- Karegoudar, Timmanagouda B. , Chae, Jong Chan , Kim, Chi Kyung
- J. Microbiol. 1999;37(3):123-127.
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Abstract
- A Pseudomonas sp. strain DJ-12 isolated by 4-cholrobiphenyl enrichment culture technique is capable of utilizing 4-hydroxybenzoic acid as a sole source of carbon and energy. The bacterium catabolized 4-hydroxybenzoic acid through the intermediate formation of protocatechuic acid, which was further metabolized. The cell free extracts of pseudomonas sp. DJ-12, grown on 4-hydroxybenzoic acid showed higher activities of 4-hydroxyenzoate 3-hydroxylase and protocatechuate 4,5-dioxygenase, but the activity of catechol 2,3-dioxygenase was lower. The results suggest that 4-hydroxybenzoic acid is catabolized via protocatechuic acid rather than catechol or gentisic acid in this bacterium and that the protocatechuic acid formed was metabolized through a metacleavage pathway by protocatechuate 4,5-dioxygenase.
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