O'Connor K, Buckley C M, Hartmans S, Dobson A D
Food Microbiology Department, University College, Cork, Ireland.
Appl Environ Microbiol. 1995 Feb;61(2):544-8. doi: 10.1128/aem.61.2.544-548.1995.
Styrene metabolism in styrene-degrading Pseudomonas putida CA-3 cells has been shown to proceed via styrene oxide, phenylacetaldehyde, and phenylacetic acid. The initial step in styrene degradation by strain CA-3 is oxygen-dependent epoxidation of styrene to styrene oxide, which is subsequently isomerized to phenylacetaldehyde. Phenylacetaldehyde is then oxidized to phenylacetic acid. Styrene, styrene oxide, and phenylacetaldehyde induce the enzymes involved in the degradation of styrene to phenylacetic acid by P. putida CA-3. Phenylacetic acid-induced cells do not oxidize styrene or styrene oxide. Thus, styrene degradation by P. putida CA-3 can be subdivided further into an upper pathway which consists of styrene, styrene oxide, and phenylacetaldehyde and a lower pathway which begins with phenylacetic acid. Studies of the repression of styrene degradation by P. putida CA-3 show that glucose has no effect on the activity of styrene-degrading enzymes. However, both glutamate and citrate repress styrene degradation and phenylacetic acid degradation, showing a common control mechanism on upper pathway and lower pathway intermediates.
在降解苯乙烯的恶臭假单胞菌CA-3细胞中，苯乙烯代谢已被证明是通过环氧苯乙烯、苯乙醛和苯乙酸进行的。菌株CA-3降解苯乙烯的第一步是苯乙烯在氧气依赖下环氧化为环氧苯乙烯，随后环氧苯乙烯异构化为苯乙醛。然后苯乙醛被氧化为苯乙酸。苯乙烯、环氧苯乙烯和苯乙醛诱导恶臭假单胞菌CA-3将苯乙烯降解为苯乙酸所涉及的酶。苯乙酸诱导的细胞不会氧化苯乙烯或环氧苯乙烯。因此，恶臭假单胞菌CA-3对苯乙烯的降解可进一步细分为一个由苯乙烯、环氧苯乙烯和苯乙醛组成的上途径和一个从苯乙酸开始的下途径。对恶臭假单胞菌CA-3抑制苯乙烯降解的研究表明，葡萄糖对苯乙烯降解酶的活性没有影响。然而，谷氨酸和柠檬酸盐都抑制苯乙烯降解和苯乙酸降解，这表明对上途径和下途径中间体存在共同的控制机制。
