Biomaterial Database

Production & purification of recombinant tumour necrosis factor-beta. 1993

K W Mak, and K C Loh, and M G Yap

Department of Chemical Engineering, National University of Singapore.

The effects of medium composition, temperature and tryptophan concentration on the growth and expression of a recombinant E. coli producing human tumour necrosis factor-beta (TNF-beta) were examined in shake flask cultures. We found that lower cultivation temperatures of 25 degrees C and 30 degrees C gave the best yield of soluble TNF-beta. A higher expression of total TNF-beta was obtained in defined medium. Fed-batch fermentations further confirmed that a lower mu was critical to obtaining high TNF-beta expression. This was shown to be due to the dilution effect at high mu, which affected the cell plasmid content. We found that we were unable to repress TNF-beta expression with tryptophan and TNF-beta was expressed in non-induced cultures. This has been attributed to the nature of the constructed clone, which is a low aporepressor producer, but carried a high copy number plasmid with a mutated rom gene. A rapid and improved method for the purification of TNF-beta has also been developed. The method utilised sequential steps of polyethyleneimine (PEI) and ammonium sulphate precipitation to remove most of the extraneous proteins and nucleic acids from the cell extracts. This was followed by DEAE chromatography. This procedure was found to be highly efficient and was used to purify large quantities of TNF-beta. Compared to an earlier protocol which did not include the PEI step, yields were higher and processing time was much shorter.

UI	MeSH Term	Description	Entries
D008233	Lymphotoxin-alpha	A tumor necrosis factor family member that is released by activated LYMPHOCYTES. Soluble lymphotoxin is specific for TUMOR NECROSIS FACTOR RECEPTOR TYPE I; TUMOR NECROSIS FACTOR RECEPTOR TYPE II; and TUMOR NECROSIS FACTOR RECEPTOR SUPERFAMILY, MEMBER 14. Lymphotoxin-alpha can form a membrane-bound heterodimer with LYMPHOTOXIN-BETA that has specificity for the LYMPHOTOXIN BETA RECEPTOR.	TNF Superfamily, Member 1,TNF-beta,Tumor Necrosis Factor Ligand Superfamily Member 1,Tumor Necrosis Factor-beta,Lymphotoxin,Lymphotoxin-alpha3,Soluble Lymphotoxin-alpha,alpha-Lymphotoxin,Lymphotoxin alpha,Lymphotoxin alpha3,Lymphotoxin-alpha, Soluble,Soluble Lymphotoxin alpha,Tumor Necrosis Factor beta,alpha Lymphotoxin
D010957	Plasmids	Extrachromosomal, usually CIRCULAR DNA molecules that are self-replicating and transferable from one organism to another. They are found in a variety of bacterial, archaeal, fungal, algal, and plant species. They are used in GENETIC ENGINEERING as CLONING VECTORS.	Episomes,Episome,Plasmid
D011994	Recombinant Proteins	Proteins prepared by recombinant DNA technology.	Biosynthetic Protein,Biosynthetic Proteins,DNA Recombinant Proteins,Recombinant Protein,Proteins, Biosynthetic,Proteins, Recombinant DNA,DNA Proteins, Recombinant,Protein, Biosynthetic,Protein, Recombinant,Proteins, DNA Recombinant,Proteins, Recombinant,Recombinant DNA Proteins,Recombinant Proteins, DNA
D003470	Culture Media	Any liquid or solid preparation made specifically for the growth, storage, or transport of microorganisms or other types of cells. The variety of media that exist allow for the culturing of specific microorganisms and cell types, such as differential media, selective media, test media, and defined media. Solid media consist of liquid media that have been solidified with an agent such as AGAR or GELATIN.	Media, Culture
D004926	Escherichia coli	A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.	Alkalescens-Dispar Group,Bacillus coli,Bacterium coli,Bacterium coli commune,Diffusely Adherent Escherichia coli,E coli,EAggEC,Enteroaggregative Escherichia coli,Enterococcus coli,Diffusely Adherent E. coli,Enteroaggregative E. coli,Enteroinvasive E. coli,Enteroinvasive Escherichia coli
D005285	Fermentation	Anaerobic degradation of GLUCOSE or other organic nutrients to gain energy in the form of ATP. End products vary depending on organisms, substrates, and enzymatic pathways. Common fermentation products include ETHANOL and LACTIC ACID.	Fermentations
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D013696	Temperature	The property of objects that determines the direction of heat flow when they are placed in direct thermal contact. The temperature is the energy of microscopic motions (vibrational and translational) of the particles of atoms.	Temperatures
D014364	Tryptophan	An essential amino acid that is necessary for normal growth in infants and for NITROGEN balance in adults. It is a precursor of INDOLE ALKALOIDS in plants. It is a precursor of SEROTONIN (hence its use as an antidepressant and sleep aid). It can be a precursor to NIACIN, albeit inefficiently, in mammals.	Ardeydorm,Ardeytropin,L-Tryptophan,L-Tryptophan-ratiopharm,Levotryptophan,Lyphan,Naturruhe,Optimax,PMS-Tryptophan,Trofan,Tryptacin,Tryptan,Tryptophan Metabolism Alterations,ratio-Tryptophan,L Tryptophan,L Tryptophan ratiopharm,PMS Tryptophan,ratio Tryptophan