StXyl43A（exo-β-1,3-Xylosidase）
StXyl43A
Ex-Xyl0163
(EC.3.2.1.72) exo-β-1,3-Xylosidase
CAZy Family: GH43
PROPERTIES
1.ELECTROPHORETIC PURITY
-Single band on SDS-gel electrophoresis (MW ~58kDa)
Figure 1. Electrophoresis analysis of StXyl43A. M, molecular weight marker (PageRuler Prestained Protein Ladder, Thermo Scientific); lane 1, culture lysate before IPTG induction; lane 2, culture lysate after IPTG induction; lane 3, StXyl43A purified from Ni sepharose fastflow column.
2.SPECIFIC ACTIVITY
0.09 U/mg protein (on pNP-β-xyl) at pH 6.0 and 45°C
One Unit of pNP-β-xylactivity is defined as the amount of enzyme required to release 1 μmol of pNP per minute from pNP-β-xyl in KPB(20mM) pH6.0.
3.RELATIVE RATES OF HYDROLYSIS OF SUBSTRATES
Table 1. Substrate specifificity of StXyl43A on polysaccharides.
Figure2. High-performance anion-exchange chromatography (HPAEC) analysis of β-1,3-Xyl2 (a), β-1,4-Xyl2 (b), and β-1,3-xylooligosaccharides (c) reaction products with rSWU43A. Reaction mixtures containing 0.1 mL of 4 μg/mL substrate in 20 mM potassium phosphate buffffer (pH 6.0) and 5 mU of rSWU43A were incubated at 45 °C for the time periods shown, followed by analysis of the reaction products by HPAEC.
4.PHYSICOCHEMICAL PROPERTIES
pH Optima:6.5
pH Stability: 3.0-9.0
Temperature Optima:40oC
Temperature Stability:20-40oC
Figure3. Effffects of pH (a) and temperature (b) on the activity (dotted lines) and stability (solid lines) of StXyl43A.
5.STORAGE CONDITIONS
The enzyme should be stored at -20°C. For assay, this enzyme should be diluted in phosphate buffer (20 mM) pH7.0. Swirl to mix the enzyme immediately prior to use.
6. REFERENCES
[1] Ye Yuan, Xinyu Zhang, Han Zhang, et al. Identifification and characterization of the first β-1,3-D-xylosidase from a gram-positive bacterium,Streptomycessp. SWU10[J].Enzyme and Microbial Technology, 2018,112:72-78.
