title: Methyl alpha-D-glucopyranoside enhances the enzymatic activity of recombinant beta-galactosidase inclusion bodies in the araBAD promoter system of Escherichia coli.
abstract: In this study, we utilized a catabolite repressor to improve the enzymatic activity of recombinant beta-galactosidase inclusion bodies (IBs) produced in Escherichia coli under the araBAD promoter system. Specifically, we employed methyl alpha-D: -glucopyranoside (alpha-MG) to lower the transcription rate of the beta-galactosidase structural gene. In deepwell microtiter plate and lab-scale fermentor culture systems, we demonstrated that the addition of alpha-MG after induction improved the specific beta-galactosidase production, even though beta-galactosidase was still produced as an IB. Particularly, the addition of 0.0025% alpha-MG led to the most significant increase in the specific activity of the beta-galactosidase. Interestingly, the beta-galactosidase IBs obtained in the presence of 0.0025% alpha-MG were more loosely packed, as determined by IB solubilization in guanidine hydrochloride solution. We propose that the reduced gene transcription rate was responsible for the increased specific beta-galactosidase activity and the loose packing that characterized the IBs produced in the presence of alpha-MG. This principle could be applied throughout the enzyme bioprocessing industry in order to enhance the activity of aggregate-prone enzymes within IBs.
authors.affiliation: Division of Food and Biotechnology, Chungju National University, Jeungpyung-Gun, Chungbuk 368-701, South Korea. khjung@cjnu.ac.kr
authors.forename: Kyung-Hwan
authors.initials: KH
authors.lastname: Jung
authors.forename: Ji-Hyeon
authors.initials: JH
authors.lastname: Yeon
authors.forename: Sung-Kwon
authors.initials: SK
authors.lastname: Moon
authors.forename: Joon Ho
authors.initials: JH
authors.lastname: Choi
mesh_terms: D015536:Down-Regulation; D020536:Enzyme Activators / Q000494:pharmacology*; D004926:Escherichia coli / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression / Q000187:drug effects; D002479:Inclusion Bodies / Q000201:enzymology*; D008757:Methylglucosides / Q000494:pharmacology*; D011401:Promoter Regions, Genetic; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D001616:beta-Galactosidase / Q000235:genetics / Q000378:metabolism*
chemical_list: D020536:Enzyme Activators; D029968:Escherichia coli Proteins; D008757:Methylglucosides; D011994:Recombinant Proteins; C027020:methylglucoside; D001616:beta-Galactosidase