Fig. 2
![Fig. 2](http://media.springernature.com/full/springer-static/image/art%3A10.1186%2Fs13068-018-1299-1/MediaObjects/13068_2018_1299_Fig2_HTML.png)
SDS-PAGE analysis of MtCh509 from M. thermotolerans DAU221. Lane 1, Protein molecular mass marker; lane 2, soluble protein extracted from E. coli cells over-expressing His6-MtCh509; lane 3, MtCh509 purified by His-tag affinity chromatography; lane 4, zymogram of MtCh509