In this experiment,the genome of R.flavefaciens was used as a template,and the target gene xynB was amplified by PCR,and the recombinant vector PET28a-xynB was obtained by ligating xynB with the expression vector PET28a.The expression of Escherichia coli BL21(DE3)containing recombinant vector was induced by IPTG,and its enzymatic properties were detected after purification by nickel ion chromatogram.After bioinformatics analysis,it was found that the theoretical size of XynB was 47 kDa,the predicted isoelectric point was 4.49,there was no signal peptide,it contained a glycoside hydrolase 11 family domain and a carbohydrate binding domain.The results of enzymatic properties showed that the optimal pH of the enzyme was 5.0.The optimal reaction temperature was 40℃.The metal ions Mg2+,Na+,K+and Ba2+had a good activation effect on XynB.In conclusion,R.flavefaciens xylanase XynB belonged to the GH11 family,with an optimal pH of 5.0,an optimal temperature of 40℃,and an enzyme specific activity of 62.94 U/mg.
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