重组毕赤酵母表达reteplase发酵过程中的降解现象  

Degradation of Reteplase Expressed by Recombinant Pichia pastoris

作　　者：方曙光[1] 储炬[1] 黄立[1] 庄英萍[1] 张嗣良[1] 

机构地区：[1]华东理工大学生物反应器工程国家重点实验室国家生化工程技术研究中心,上海200237

出　　处：《华东理工大学学报（自然科学版）》2006年第12期1413-1417,共5页Journal of East China University of Science and Technology

基　　金：国家"十五"高新技术发展计划(863计划)项目(2002AA217021);国家重大科技专项项目(2002AA2Z3451)

摘　　要：研究了pH和温度对重组毕赤酵母表达retep lase(rPA)发酵过程中的降解现象。在低pH(4.5)诱导条件下,由于蛋白酶活性高,rPA降解严重,表达量几乎为0,提高诱导pH至6.5,蛋白酶活性降低,rPA的表达量最高达到122 m g/L。通过将诱导温度从30°C降低到20°C,rPA的表达量从153.2 m g/L提高到207.9 m g/L。降低温度能减少细胞死亡率,从而减少了发酵液中蛋白酶的释放,降低了蛋白酶的活性,抑制了对目的蛋白rPA的降解。另外,低温使胞内AOX酶活性提高,从而增强了rPA的表达。The effect of pH and temperature on the degradation of reteplase（rPA） expressed by recombinant Pichia pastoris was investigated. Under lower pH cultures （pH 4.5）, rapid degradation of rPA was observed, increasing the induction pH from 4. 5 to 6.5 resulted in an increase of the rPA production from nil to 122 mg/L, which is attributed to the decrease of protease activity in the culture broth. When induction temperatures reduced from 30 ℃ to 20 ℃, the yield of recombinant rPA increased from 153.2 mg/L to 207.9 mg/L. Analyses of protease, cell viability and alcohol oxidase （AOX） activity showed that cultures at lower temperature not only led to a reduced cell death rate, and hence a lower amount of host cell proteases in the supernatant, but also significant increase in AOX activity, which might be favorable to the rPA expression.

关 键 词：毕赤酵母 RETEPLASE 降解 发酵 

分 类 号：Q93[生物学—微生物学]