To improve the inulinase application in biotechnology, the characteristic of inulinase from Kluyveromyces marxianus YX01 was investigated. The inu gene of K. marxianus YX01 was transformed into Pichiapastoris GS115 host cells with molecular biology techniques. Then we achieved the heterologous expression of exo-inulinase whose molecular mass was about 86.0 kDa by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Furthermore, six His-tag was added to the inulinase and a two-step method was applied in the purification of inulinase, including concentration via dialysis by polyethylene glycol 20 000 and metal Ni-NTA Agarose affinity adsorption. The purification factor of purified protein was 3.6 and the recovery rate of enzyme activity was 33.1%. We characterized the purified inulinase. The optimum temperature was 60 degrees C and pH was 4.62. When inulin and sucrose were used as substrates, the K(m) and V(max) values were 80.53 g/L vs 4.49 g/(L x min) and 183.10 g/L vs 20.20 g/(L x min), respectively. In addition, metal ions including Mn2+, Ca2+, Cu2+, Zn2+ and Fe2+ exhibited different degrees of inhibition on the enzyme activity, and Cu2+, Zn2+ and Fe2+ exhibited the most significant inhibition. Our findings might lay a good foundation for industrial application of inulinase.
Glycoside Hydrolases ; chemistry ; genetics ; Industrial Microbiology ; Inulin ; Kluyveromyces ; enzymology ; genetics ; Pichia ; Sucrose ; Temperature

AIM: To observe effects of shear stress and TNF-? on caveolin-1 expression. METHODS: Cultured human aortic endothelial cells (HAECs) of passage 3-5 were used in the experiment. Cells were exposed to a laminar flow (shear stress 1.0 Pa) by using a parallel rectangular flow chamber for different time. Caveolin-1 mRNA and protein expression were measured by RT-PCR and Western blot, respectively. Caveolin-1 expression of the cells stimulated by TNF-? were also studied to elucidate the influence of this inflammatory factor. RESULTS: After 24 h of exposure to 1.0 Pa shear stress, both of caveolin-1 protein and mRNA expression decreased in HAECs, especially caveolin-1 mRNA expression (P

OBJECTIVE To investigate the effect of Jianpi Yangzheng(JPYZ)formula regulating tumor-associated macrophage(TAM)exosomes on anoikis in gastric cancer and its mechanism.METHODS TAM model was established by inducing human mononuclear THP-1 cells in vitro;M0,TAM and TAM+JPYZ formula exosomes were extracted by ultracentrifugation and co-incuba-ted with gastric cancer cells.Flow cytometry was used to detect the effect of exosomes in each group on anoikis in gastric cancer cells.A BALB/c transplanted tumor mouse model was constructed,and the expression level of apoptotic proteins in transplanted tumors was detected by Western blot.Label-free mass spectrometry proteomics and bioinformatics were used to analyze the differential proteins in gastric cancer cells before and after intervention;Western blot and qPCR experiments were used to detect the expression level of dif-ferential protein isocitrate dehydrogenase 1(IDH1),and ubiquitination experiments were used to detect the ubiquitination level of IDH1;kits were used to detect the levels of α-ketoglutarate(α-KG),NADPH/NADP+,glutathione(GSH/GSSG)and reactive oxy-gen species(ROS)content.RESULTS The anoikis rate of gastric cancer cells was reduced after TAM exosomes intervention(P<0.05,P<0.01),while it was significantly increased after TAM+JPYZ exosomes intervention(P<0.05,P<0.01).In the in vivo mouse experiment,the ratio of Cleaved Caspase-3/Caspase-3 in the tumor of the TAM exosome group was reduced(P<0.05),while the ra-tio was significantly increased after TAM+JPYZ exosome intervention(P<0.05).Proteomic analysis showed that IDH1 was significant-ly different after intervention,and was related to tricarboxylic acid cycle metabolism.Compared with the M0 group,the IDH1 ubiquiti-nation level of gastric cancer cells in the TAM group with exosome intervention was increased,the levels of α-KG,NADPH/NADP+and GSH/GSSG were significantly increased,and the ROS content was reduced(P<0.05),while TAM+JPYZ exosomes could reverse the above phenomenon.CONCLUSION JPYZ Formula can regulate TAM exosomes to cause ubiquitin degradation of IDH1 in gas-tric cancer cells,reduce the level of tricarboxylic acid cycle metabolism in gastric cancer cells,promote ROS accumulation,induce anoikis in gastric cancer,and thus inhibit the development of gastric cancer.