摘要
海洋假单胞菌Pseudomonas stutzeri DEH138A可以产生两种诱导型脱卤酶,即L-卤代酸脱卤酶(LDEX)和D-卤代酸脱卤酶(D-DEX)。用DL-2-氯丙酸(DL-2-CPA)、D-2-氯丙酸(D-2-CPA)和L-2-氯丙酸(L-2-CPA)3种诱导物分别作为种子培养与发酵培养碳源,诱导菌株DEH138A,通过HPLC检测反应体系中氯丙酸的剩余量来评估酶活性,研究底物对其酶活性的影响,并优化培养方式,实现单一构型卤代酸脱卤酶的定向诱导。结果表明:L-2-CPA可定向诱导L-DEX的产生,L-2-CPA作为唯一碳源诱导时得到的L-DEX酶活性是D-DEX酶活性的85倍,优化培养获得的LDEX和D-DEX最高酶活性分别为6.11×10-2、3.23×10-3U/mL(培养基),与DL-2-CPA作为诱导底物时相比较,分别提高了5.1倍和2.3倍。研究表明,L-2-CPA具有诱导专一性,实现了L-DEX的定向诱导,但对于D-DEX,则不能用L-DEX被相应构型底物诱导产生的机理解释,有待进一步研究。
The effects of carbon source substrates DL-2-chloropropionic acid（ DL-2-CPA） , L-2-chloropropionic acid（L-2-CPA） and D-2-chloropropionic acid（D-2-CPA） on induction of 2-haloacid dehalogenases L-2-haloacid dehalogenase（ L-DEX） and D-2-haloacid dehalogenase（ D-DEX） were studied and culture process was optimized in marine bacterium Pseudomonas stutzeri DEH138A. The residual chloropropionic acid in the reaction system was quantified by HPLC. The L-2-CPA as sole carbon source was shown to specifically induce L-DEX production, with 84 times higher activity than D-DEX. The maximum activities of L-DEX （6. 11×10-2 U/mL media） and D-DEX （3. 23×10-3 U/mL media） were observed under culture condition of sole carbon source of L-2-CPA, 5. 1 times and 2. 3 times as the induction of DL-2-CPA. The findings indicate that L-2-CPA shows spe-cificity for directional induction of L-DEX. For D-DEX, however, it is not explained by the mechanism of L-DEX which is induced by corresponding substrate, and the induction of D-DEX needs to be further studied.
出处
《大连海洋大学学报》
CAS
CSCD
北大核心
2014年第4期381-385,共5页
Journal of Dalian Ocean University
基金
国家"973"重点基础研究发展计划项目(2009CB724700)
中国科学院百人计划项目(A1097)
国家自然科学基金资助项目(31100092)
关键词
假单胞菌
脱卤酶
氯丙酸
诱导
Pseudomonas stutzeri
dehalogenases
chloropropionic acid
induction
