药学论文-Val、Ile及Leu对必特螺旋霉素生物合成的影响.doc

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1、药学论文-Val、Ile及Leu对必特螺旋霉素生物合成的影响        作者：李桢林江维王永红*郝玉有储炬庄英萍张嗣良【摘要】 在合成培养基中分别添加缬氨酸(Val)、异亮氨酸(Ile)与亮氨酸(Leu)考察其对必特螺旋霉素生物合成的影响，证明Val、Ile及Leu对必特螺旋霉素多组分的合成有着不同的调节作用。实验结果表明在36h分别添加0.5g/L的上述三种氨基酸，发酵液pH和铵离子浓度存在着显著差异，而Val脱氢酶活性都增加了2～3倍。添加Val使菌体在60h之前糖耗速率加快，达到1.0g/(L·h)，

2、胞内丙酮酸积累，丙酮酸羧化酶活性增加20%～95%，柠檬酸合成酶活性降低41%，发酵液中丙酸和丁酸出现先增加后降低的现象，最终效价比对照高出45.3%，而总异戊酰组分则降低了23%，其他酰化组分降低了39.6%；添加Ile以后菌体糖耗速率降至对照的30%～40%，柠檬酸合成酶活性降低了47%，发酵液中的乙酸、丙酸、丁酸都出现大量积累的现象。最终效价为对照的85%，而丙酰螺旋霉素III、乙酰螺旋霉素以及异丁酰螺旋霉素组分含量分别增加126%、50%、296%。添加Leu对初级代谢影响不大，异戊酸在胞外积累，随后被

3、重新吸收利用，最终异戊酰基螺旋霉素II和异戊酰基螺旋霉素III组分分别提高了41%和50%。同时总异戊酰基螺旋霉素相对含量也比对照提高了41.9%，效价和对照基本一致。【关键词】 必特螺旋霉素；缬氨酸；亮氨酸；异亮氨酸；有机酸；铵离子   ABSTRACT Thispaperdemonstratedthatsupplementingvaline(L-Val),isoleucine(L-Ile)andleucine(L-Leu)insyntheticmediahaddifferenteffectsonbiosyn

4、thesisofmulti-componentsofbiotechspiramycin.Theresultsshowedthatthesupplementof0.05g/100mlaminoacidsafter36hoffermentationresultedindifferentpHvaluesandammoniumionconcentrationsoffermentationbroth,and2to3time-increaseoftheactivityofvalinedehydrogenase.Within

5、60hafterthesupplementofL-Val,theglucoseconsumptionratewasincreasedto0.1g/(100ml·h),pyruvicacidwasaccumulatedinsidethecells,theactivityofpyruvatecarboxylase(PC)wasincreasedintherangeof20%～95%,theactivityofcitratesynthase(CS)wasdecreasedby41%,thepropionicacida

6、ndbutyricacidinthefermentationbrothwereincreasedatfirstandthendecreasedwiththeultimatebiologicaltiterofbiotechspiramycinbeing45.3%higherthanthatofthecontrolgroup,therelativecontentoftotalisovalerylspiramycincomponentsweredecreasedby23%,andtherelativecontento

7、fotheracylatedcomponentswasdeclinedby39.6%.AfterthesupplementofL-Ile,theglucoseconsumptionratewasdecreasedto30%～40%thenthatofthecontrolgroup,theactivityofCSwasdecreasedby47%,largeamountsofaceticacid,propionicacidandbutyricacidinthefermentationbrothwereaccumu

8、latedinthecellswiththeultimatebiologicaltiterofbiotechspiramycinbeing85%(ofthat)ofthecontrolgroup,andtherelativecontentofpropionylspiramycinIII,acetylspiramycinandisobutyrylspiramycincomponentwe