Biomaterial Database

DNA polymerases from the extremely thermophilic bacterium Thermus thermophilus HB-8. 1985

C Rüttimann, and M Cotorás, and J Zaldívar, and R Vicuña

Three DNA polymerase isoenzymes, which have been called A, B and C, were purified from Thermus thermophilus HB-8. These enzymes can be separated by chromatography (pH 7.5) on phosphocellulose and DNA-agarose. Their relative molecular masses, as determined by glycerol gradient centrifugation, fall in the range of 110000-120000. The three of them are devoid of exonuclease activity. Species A, B and C differ in their sensitivity towards N-ethylmaleimide (A greater than B greater than C) and urea (A greater than B = C) and also in their stability at high temperature (90 degrees C) (B greater than C greater than A). In addition, these enzymes can be distinguished utilizing various templates under different conditions. Thus, with activated DNA and Mg2+ as a cofactor, the highest incorporation is obtained at 50 degrees C with enzyme A and at 63 degrees C with enzymes B and C. If Mg2+ is replaced by Mn2+, the optimal temperatures remain unchanged, but enzyme A is stimulated twofold, while the activities of enzymes B and C decrease to one-half. On the other hand, with either poly(dA) X (dT)10 or poly(dA-dT) and Mg2+, enzyme A is inactive and enzyme C is severalfold more active than enzyme B. With the former synthetic template, optimal temperatures are 50 degrees C (enzyme C) and 40 degrees C (enzyme B), while with poly(dA-dT) they both work best at 63 degrees C. In turn, only enzyme C is able to utilize poly(rA) X (dT)10, although only with Mn2+ as a cofactor.

UI	MeSH Term	Description	Entries
D008970	Molecular Weight	The sum of the weight of all the atoms in a molecule.	Molecular Weights,Weight, Molecular,Weights, Molecular
D002499	Centrifugation, Density Gradient	Separation of particles according to density by employing a gradient of varying densities. At equilibrium each particle settles in the gradient at a point equal to its density. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)	Centrifugations, Density Gradient,Density Gradient Centrifugation,Density Gradient Centrifugations,Gradient Centrifugation, Density,Gradient Centrifugations, Density
D002621	Chemistry	A basic science concerned with the composition, structure, and properties of matter; and the reactions that occur between substances and the associated energy exchange.
D002846	Chromatography, Affinity	A chromatographic technique that utilizes the ability of biological molecules, often ANTIBODIES, to bind to certain ligands specifically and reversibly. It is used in protein biochemistry. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)	Chromatography, Bioaffinity,Immunochromatography,Affinity Chromatography,Bioaffinity Chromatography
D004259	DNA-Directed DNA Polymerase	DNA-dependent DNA polymerases found in bacteria, animal and plant cells. During the replication process, these enzymes catalyze the addition of deoxyribonucleotide residues to the end of a DNA strand in the presence of DNA as template-primer. They also possess exonuclease activity and therefore function in DNA repair.	DNA Polymerase,DNA Polymerases,DNA-Dependent DNA Polymerases,DNA Polymerase N3,DNA Dependent DNA Polymerases,DNA Directed DNA Polymerase,DNA Polymerase, DNA-Directed,DNA Polymerases, DNA-Dependent,Polymerase N3, DNA,Polymerase, DNA,Polymerase, DNA-Directed DNA,Polymerases, DNA,Polymerases, DNA-Dependent DNA
D005033	Ethylmaleimide	A sulfhydryl reagent that is widely used in experimental biochemical studies.	N-Ethylmaleimide,N Ethylmaleimide
D006358	Hot Temperature	Presence of warmth or heat or a temperature notably higher than an accustomed norm.	Heat,Hot Temperatures,Temperature, Hot,Temperatures, Hot
D013379	Substrate Specificity	A characteristic feature of enzyme activity in relation to the kind of substrate on which the enzyme or catalytic molecule reacts.	Specificities, Substrate,Specificity, Substrate,Substrate Specificities
D013824	Thermus	Gram-negative aerobic rods found in warm water (40-79 degrees C) such as hot springs, hot water tanks, and thermally polluted rivers.
D014508	Urea	A compound formed in the liver from ammonia produced by the deamination of amino acids. It is the principal end product of protein catabolism and constitutes about one half of the total urinary solids.	Basodexan,Carbamide,Carmol