Biomaterial Database

Thermostable alanine racemase from Bacillus stearothermophilus: molecular cloning of the gene, enzyme purification, and characterization. 1986

K Inagaki, and K Tanizawa, and B Badet, and C T Walsh, and H Tanaka, and K Soda

The alanine racemase (EC 5.1.1.1) gene of a thermophilic bacterium, Bacillus stearothermophilus, was cloned and expressed in Escherichia coli C600 with vector plasmid pICR301, which was constructed from pBR322 and the L-alanine dehydrogenase gene derived from B. stearothermophilus. A coupled assay method with L-alanine dehydrogenase and tetrazolium salts was used to detect visually the alanine racemase activity in the clones. Alanine racemase overproduced in a clone carrying the plasmid pICR4, 12 kilobases of DNA, was purified from cell extracts about 340-fold to homogeneity by five steps including heat treatment. The overproduced enzyme was confirmed to originate from B. stearothermophilus by an immunochemical cross-reaction with the enzyme of B. stearothermophilus. The purified enzyme has a molecular weight of about 78 000 and consists of two identical subunits of Mr of 39 000. At the optimum temperature (50 degrees C), the enzyme has a specific activity of 1800 units/mg (Vmax, D- to L-alanine). Resolution and reconstitution experiments together with the absorption spectrum of the enzyme clearly indicate that alanine racemase of B. stearothermophilus is a pyridoxal 5'-phosphate enzyme.

UI	MeSH Term	Description	Entries
D007106	Immune Sera	Serum that contains antibodies. It is obtained from an animal that has been immunized either by ANTIGEN injection or infection with microorganisms containing the antigen.	Antisera,Immune Serums,Sera, Immune,Serums, Immune
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
D003001	Cloning, Molecular	The insertion of recombinant DNA molecules from prokaryotic and/or eukaryotic sources into a replicating vehicle, such as a plasmid or virus vector, and the introduction of the resultant hybrid molecules into recipient cells without altering the viability of those cells.	Molecular Cloning
D004262	DNA Restriction Enzymes	Enzymes that are part of the restriction-modification systems. They catalyze the endonucleolytic cleavage of DNA sequences which lack the species-specific methylation pattern in the host cell's DNA. Cleavage yields random or specific double-stranded fragments with terminal 5'-phosphates. The function of restriction enzymes is to destroy any foreign DNA that invades the host cell. Most have been studied in bacterial systems, but a few have been found in eukaryotic organisms. They are also used as tools for the systematic dissection and mapping of chromosomes, in the determination of base sequences of DNAs, and have made it possible to splice and recombine genes from one organism into the genome of another. EC 3.21.1.	Restriction Endonucleases,DNA Restriction Enzyme,Restriction Endonuclease,Endonuclease, Restriction,Endonucleases, Restriction,Enzymes, DNA Restriction,Restriction Enzyme, DNA,Restriction Enzymes, DNA
D004355	Drug Stability	The chemical and physical integrity of a pharmaceutical product.	Drug Shelf Life,Drugs Shelf Lives,Shelf Life, Drugs,Drug Stabilities,Drugs Shelf Life,Drugs Shelf Live,Life, Drugs Shelf,Shelf Life, Drug,Shelf Live, Drugs,Shelf Lives, Drugs
D005779	Immunodiffusion	Technique involving the diffusion of antigen or antibody through a semisolid medium, usually agar or agarose gel, with the result being a precipitin reaction.	Gel Diffusion Tests,Diffusion Test, Gel,Diffusion Tests, Gel,Gel Diffusion Test,Immunodiffusions,Test, Gel Diffusion,Tests, Gel Diffusion
D005796	Genes	A category of nucleic acid sequences that function as units of heredity and which code for the basic instructions for the development, reproduction, and maintenance of organisms.	Cistron,Gene,Genetic Materials,Cistrons,Genetic Material,Material, Genetic,Materials, Genetic
D005798	Genes, Bacterial	The functional hereditary units of BACTERIA.	Bacterial Gene,Bacterial Genes,Gene, Bacterial
D006358	Hot Temperature	Presence of warmth or heat or a temperature notably higher than an accustomed norm.	Heat,Hot Temperatures,Temperature, Hot,Temperatures, Hot
D000411	Alanine Racemase	A pyridoxal-phosphate protein that reversibly catalyzes the conversion of L-alanine to D-alanine. EC 5.1.1.1.	Racemase, Alanine