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先将人Zeta型谷胱甘肽硫转移酶1c-1c(hGSTZ1c-1c)中非催化中心的Cys-137,Cys-154,Cys-165和Cys-205突变为Ser,然后将催化中心14,15和17位的3个氨基酸残基突变为Cys,再利用半胱氨酸缺陷型大肠杆菌表达系统将其特定地转化为Sec,即把GPx的催化基团引入到hGSTZ1c-1c中,高效地获得了具有谷胱甘肽过氧化物酶(GPx)活力的模拟酶.其中制备的3个含硒突变体15C,14C/15C和17C均显示出明显的GPx活力.对非含硒突变体性质研究发现,Ser-14或Ser-15任何一个残基发生突变都会导致hGSTZ1c-1c的GST活力几乎丧失,表明Ser-14和Ser-15在催化反应中发挥着重要作用,但前者主要参与底物结合,后者更侧重于催化.
Cys-137, Cys-154, Cys-165 and Cys-205 in the non-catalytic center of human Zeta-type glutathione S-transferase 1c-1c (hGSTZ1c-1c) were first mutated to Ser, and then catalytic center 14, The three amino acid residues at positions 15 and 17 were mutated to Cys, which was specifically converted to Sec using the cysteine-deficient E. coli expression system, ie introducing the catalytic group of GPx into hGSTZlc-Ic efficiently The mimetic enzyme with glutathione peroxidase (GPx) activity was obtained, and all the three selenium-containing mutants 15C, 14C / 15C and 17C showed obvious GPx activity. It was found that any mutation of either Ser-14 or Ser-15 resulted in almost loss of GST activity of hGSTZ1c-1c, indicating that Ser-14 and Ser-15 play an important role in the catalytic reaction, but the former is mainly involved in the substrate The latter is more focused on catalysis.