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Table 1 Protein quantification and activity assaysa

From: Streamlined protein expression and purification using cleavable self-aggregating tags

Product protein (molecular weight) Aggregatesb (μg/mg wet cell pellet) Quantity of purified proteinb (μg/mg wet cell pellet) Specific activity (units/mg) Specific activity reported in
the literature (units/mg)
Cleavage efficiencyc Percent recovery (mass)d
From 18A fusions  
LipA (21 kDa) 34.1 ± 4.1 10.4 ± 0.3 72.8 ± 3.9   (78 ± 2)% (68 ± 7)%
AMA (49 kDa) 19.1 ± 1.4 7.9 ± 1.0 2.3 ± 0.5   (80 ± 1)% (62 ± 3)%
XynB (61 kDa) 18.1 ± 2.0 1.6 ± 0.2 2.6 ± 0.3   (69 ± 3)% (14 ± 1)%
From ELK16 fusions  
LipA 31.0 ± 4.1 8.3 ± 0.7 133.4 ± 2.0 120 (ref. [21]) (73 ± 1)% (59 ± 4)%
AMA 23.2 ± 2.9 4.0 ± 0.1 1.8 ± 0.3 1.9-2.5 (ref. [14]) (65 ± 2)% (27 ± 3)%
XynB 17.6 ± 0.5 2.9 ± 0.1 1.5 ± 0.1 0.072-25.2e (ref. [13]) (57 ± 2)% (23 ± 1)%
  1. aThe experiments were carried out in triplicate with three independent expression clones. bYield of protein from LB culture with wet cell weight of 2.66 ± 0.99 mg/ml. cCleavage efficiency was calculated by dividing the amount of cleaved protein aggregate over that of the total aggregate before cleavage. dPercent recovery in terms of mass was calculated by dividing the mass of the free protein released into the soluble solution after cleavage over the mass of the total free protein that could be theoretically obtained from the respective protein aggregate, assuming a complete cleavage and release. eSpecific activity of xylosidase obtained from two repeated steps of purification with a DEAE-Sepharose CL-6B or DEAE-Sephadex A-50 column was 2.4 units/mg and 1.98 units/mg, respectively.