Silica mesoporous materials were synthesized and used as the supporting materials for immobilization of enzyme.Penicillin G acylase,an enzyme which was used to produce 6-APA in pharmaceutical industry,was immobilized ...Silica mesoporous materials were synthesized and used as the supporting materials for immobilization of enzyme.Penicillin G acylase,an enzyme which was used to produce 6-APA in pharmaceutical industry,was immobilized in the mesoporous materials by the immersion method.The stabilities of the immobilized penicillin G acylase were studied.After incubation at 60 ℃ for 2 h,the activity of immobilized penicillin G acylase remained 80% in the best case.At higher or lower pH,the free enzyme was deactivated quickly,while the immobilized enzyme still retained active.The result of operational stability showed that the immobilized(enzyme) retained 70% of its initial activity after operating for 6 times.These results showed that the stabilities of immobilized penicillin G acylase,related to the pore size of mesoporous materials,were increased significantly compared with those of free enzyme.The improvement of stabilities of immobilized enzyme was significant when the pore size of the mesoporous materials matched the enzyme molecule size.展开更多
首次采用冷冻-真空吸附法在介孔材料SBA-15中固定了木瓜蛋白酶.与普通的浸渍方法相比,此法不仅可以制备高组装量的固定化酶,每克载体固定量可达450 mg,同时酶的活性仍然保持,并得到较好的固定化酶性质(如高稳定性),在90℃保温30 m in仍...首次采用冷冻-真空吸附法在介孔材料SBA-15中固定了木瓜蛋白酶.与普通的浸渍方法相比,此法不仅可以制备高组装量的固定化酶,每克载体固定量可达450 mg,同时酶的活性仍然保持,并得到较好的固定化酶性质(如高稳定性),在90℃保温30 m in仍保留70%的活力.展开更多
SPAP2,a transmembrane protein,is an Ig family receptor containing both ITIMs(immunoreceptor tyrosine-based inhibition motifs) and ITAMs(immunoreceptor tyrosine-based activation motifs).The extracellular portion of SPA...SPAP2,a transmembrane protein,is an Ig family receptor containing both ITIMs(immunoreceptor tyrosine-based inhibition motifs) and ITAMs(immunoreceptor tyrosine-based activation motifs).The extracellular portion of SPAP2 contains six immunoglobulin-like domains and its intracellular segment has two ITAMs and two ITIMs.Sequence alignment with the genomic database reveals that the SPAP2 gene contains 16 exons and is localized at chromosome 1q21.SPAP2 is consisted of 734 amino acids,and the intercellular portion of SPAP2 contains 137 amino acids. Tyrosine-phosphorylated SPAP2 is specifically associated with SH2 domain-containing tyrosine kinases and SH2 domain-containing tyrosine phosphatases,which lead to the initiation of signal transduction.SPAP2CT gene was amplified by PCR with SPAP2 full-length DNA as the template and cloned to the pBluescript Ⅱ KS vector.pGex-2T-SPAP2CT,the expression vector of dissoluble fusion protein,was constructed and transferred into E.coli of DE3-plysS.The fusion protein GST-SPAP2CT was expressed efficiently and purified by FFQ ion exchange chromatography and GSH affinity chromatography.The result indicates that we have constructed steady expression vector pGex-2T-SPAP2CT, which was expressed in E.coli.The molecular weight of the dissoluble fusion protein is 46 000,the productivity of GST-SPAP2CT protein is 10% and the purity is over 90% after the purification.展开更多
文摘Silica mesoporous materials were synthesized and used as the supporting materials for immobilization of enzyme.Penicillin G acylase,an enzyme which was used to produce 6-APA in pharmaceutical industry,was immobilized in the mesoporous materials by the immersion method.The stabilities of the immobilized penicillin G acylase were studied.After incubation at 60 ℃ for 2 h,the activity of immobilized penicillin G acylase remained 80% in the best case.At higher or lower pH,the free enzyme was deactivated quickly,while the immobilized enzyme still retained active.The result of operational stability showed that the immobilized(enzyme) retained 70% of its initial activity after operating for 6 times.These results showed that the stabilities of immobilized penicillin G acylase,related to the pore size of mesoporous materials,were increased significantly compared with those of free enzyme.The improvement of stabilities of immobilized enzyme was significant when the pore size of the mesoporous materials matched the enzyme molecule size.
文摘SPAP2,a transmembrane protein,is an Ig family receptor containing both ITIMs(immunoreceptor tyrosine-based inhibition motifs) and ITAMs(immunoreceptor tyrosine-based activation motifs).The extracellular portion of SPAP2 contains six immunoglobulin-like domains and its intracellular segment has two ITAMs and two ITIMs.Sequence alignment with the genomic database reveals that the SPAP2 gene contains 16 exons and is localized at chromosome 1q21.SPAP2 is consisted of 734 amino acids,and the intercellular portion of SPAP2 contains 137 amino acids. Tyrosine-phosphorylated SPAP2 is specifically associated with SH2 domain-containing tyrosine kinases and SH2 domain-containing tyrosine phosphatases,which lead to the initiation of signal transduction.SPAP2CT gene was amplified by PCR with SPAP2 full-length DNA as the template and cloned to the pBluescript Ⅱ KS vector.pGex-2T-SPAP2CT,the expression vector of dissoluble fusion protein,was constructed and transferred into E.coli of DE3-plysS.The fusion protein GST-SPAP2CT was expressed efficiently and purified by FFQ ion exchange chromatography and GSH affinity chromatography.The result indicates that we have constructed steady expression vector pGex-2T-SPAP2CT, which was expressed in E.coli.The molecular weight of the dissoluble fusion protein is 46 000,the productivity of GST-SPAP2CT protein is 10% and the purity is over 90% after the purification.
