ZNF191 （243-368）, a new human zinc finger protein, probably relates to some hereditary diseases and cancers, To obtain adequate amount of ZNF191（243-368） for the study of its property, structure and function, three different expression systems of inclusion-body, glutathione S-transferase （GST）, and hexahistidine （6 × His） were used and compared. Among these systems, the expression level of ZNFI91（243-368） was increased in inclusion body system under a higher isopropylthio-β-D-galactoside （IPTG） concentration, but the non-target proteins were also increased more, which made its purification more difficult and the yield lower. The expression of His-tag fusion protein was almost not affected by IPTG concentration, temperature and inducing time. At a high IPTG concentration the highest expression yield for GST fusion protein was obtained. And the fusion proteins can be partially purified by a single affinity chromatography step. The fusion protein systems show advantages for expression of these proteins.
利用反相高效液相色谱(RP HPLC)与电喷雾质谱(ESI MS和MS MS)联用技术直接分析用芴甲氧羰基(Fmoc)固相多肽合成方法手工偶联合成的一个十三肽(Lys Lys Glu Ser Asp Phe Leu Met Phe Val Tyr Leu Val,Mr1617.8)粗产品,以探索RP HPLC ESI MS和MS MS在固相多肽合成产物分析和副反应机制研究中的应用.RP HPLC结果显示:合成粗产物中含有1个主成分,2个次要成分和多个微量成分;与之联用的电喷雾质谱同步准确地测定出各成分的相对分子质量(m z)并自动对各主要成分的化学结构进行了串联质谱分析.结果证明,粗产物中的主成分即为目标十三肽,另外几个主要副产物为十三肽的残缺肽或氧化肽.对色谱和生物质谱联用技术分析合成多肽的意义和副产物形成的可能机制进行了讨论.
