Aggregation as bacterial inclusion bodies does not imply inactivation of enzymes and fluorescent proteins

Table 1 Enzymatic activity or fluorescence of inclusion bodies produced in E. coli

Construct name	Reference	Functional protein	Fraction of inclusion body protein (range, %) ^a	Aggregating domain or protein (all in the N-terminal position)	Specific activity or emission ^b (enzymatic units/mg or fluorescence units/mg)		Activity of the inclusion body fraction relative to that of soluble protein (%) ^c
					Soluble protein	Inclusion bodies
VP1LAC	This work and [9]	E. coli β-galactosidase	35.6–45.9	FMDV VP1 capsid protein	698.3 ± 153.0	1162.5 ± 256.0	166.4
hDHFR	[25]	Human dihydrofolate reductase	28.4–36.8	none	8.0 10^-2 ± 2.6 10^-2	4.7 10^-3 ± 0.9 10^-3	5.9
VP1GFP	This work	Green fluorescent protein	82.5–88.4	FMDV VP1 capsid protein	359.5 ± 66.0	70.4 ± 10.1	19.5
Aβ42(F19D)-BFP	[26]	Blue fluorescent protein	61.4–65.3	Aβ42(F19D)	118.1 ± 10.2	36.3 ± 2.2	30.7

^a The percentage of protein found in inclusion bodies relative to the total intracellular amount of recombinant protein. Values were determined from different samples taken at 3 and 5 h after triggering recombinant gene expression.
^b These values were determined in samples taken between 3 and 5 h after triggering recombinant gene expression.
^c Specific activity or fluorescence emission of inclusion bodies relative to the values determined for the soluble counterpart fraction. Protein amounts were determined by Western blot analysis as described and enzymatic assays performed by conventional procedures. Excitation wavelengths were 450 nm for VP1GFP and 360 nm for Aβ42(F19D)-BFP.

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