A duplicate in the custody of the National Institute of Standards and Technology serves as the mass standard for the United States.
Precision Plus Protein™ Standard Bio-Radd Laboratories Inc). was used as molecular mass standard.
Instrument calibration was performed using the 4700 mass standard kit from Applied Biosystems Life Technologiess, Ghent, Belgium).
P is the molecular mass standard; A, B, C, and D are the fermentation samples at 0, 18, 24, and 72 h, respectively.
Lanes M protein molecular mass standard; lane K EngK; lane S ExgS; lane H EngH Fig. 3 Specific activities of recombinant EngK and ExgS against acid-swollen cellulose.
Lane 1, molecular mass standard proteins; lane 2, soluble protein fraction of E. coli BL21 (DE3) harboring pET100/D-TOPO-PhaRRe.; lane 3, PhaR purified by nickel-nitrilotriacetic acid agarose (5 μg).
The specific parameters were as follows: the ion acceleration voltage was 20 kV, the accumulating time of single scanning was 50 s, polypeptide mass standard (Kratos Analytical) serving as external standard.
a Non-reduced SDS-PAGE 12% Tris gel stained with Coomassie Brilliant Blue R-250, molecular mass standard Prestained Protein Marker (250 kDa), b HPLC analysis performed on reversed phase C18 column.
Panel B, C: Lane 1 and Lane 9, molecular mass standard protein; Lane 2, culture uninduced; Lane 3-7, inducultureture after 2, 4, 6, 8 and 10 hours; Lane 8, wild type Lb.
a Non-reduced SDS-PAGE 12% Tris gel stained with Coomassie Brilliant Blue R-250, molecular mass standard Prestained Protein Marker (250 kDa), b HPLC analysis performed on reversed phase C18 column, using HPLC peptide standard mixture.
The m/z range was 100 1000, scan time 0.2 s, interscan delay 0.02 s, with leucine encephalin (556.3 µg/mL) as a lock mass, standard flowrate 0.1 mL/min, and a mass accuracy window of 0.5 Da was used for MS data acquisition.
