Polymerase random

The polsrmerization of the CoA monomers of (i )-hydroxyalkanoate was of chain growth in a hving fashion each molecule of the polymerase initiated and catalyzed the formation of one molecule of the polymer (196-198). By utilizing this property of polymerase, random and block copolyesters were synthesized. The resulting polymer had high molecular weight (> 10 ). In the polymerization of racemic HBCoA, only thei monomer was polymerized. Furthermore, the presence of the S monomer did not reduce the polymerization rate of the R isomer. These data indicate that the S monomer does not act as competitive inhibitor for the polymerase. 

Mutagenic PGR. More recently, methods have been developed to use the PGR reaction to randomly mutagenize a defined sequence (25). The Taq polymerase used in PGR misincorporates nucleotides in a random fashion if manganese dichloride [7773-01 -5] MnGl2, is included in the reaction buffer during PGR. The Hbrary of mutagenized PGR products can be screened for the desired phenotype. 

Poly(L-malate) decomposes spontaneously to L-ma-late by ester hydrolysis [2,4,5]. Hydrolytic degradation of the polymer sodium salt at pH 7.0 and 37°C results in a random cleavage of the polymer, the molecular mass decreasing by 50% after a period of 10 h [2]. The rate of hydrolysis is accelerated in acidic and alkaline solutions. This was first noted by changes in the activity of the polymer to inhibit DNA polymerase a of P. polycephalum [4]. The explanation of this phenomenon was that the degradation was slowest between pH 5-9 (Fig. 2) as would be expected if it were acid/base-catalyzed. In choosing a buffer, one should be aware of specific buffer catalysis. We found that the polymer was more stable in phosphate buffer than in Tris/HCl-buffer. 

Differential display is a method for identifying differentially expressed genes, using anchored oligo-dT, random oligonucleotide primers and polymerase chain reaction on reverse-transcribed RNA from different cell populations. The amplified complementary DNAs are displayed and comparisons are drawn between the different cell populations. 

Leung, D.W., Chen, E. and Goeddel, D.V. (1989) A method for random mutagenesis of a defined DNA segment using a modified polymerase chain reaction. Technique, 1, 11-15. 

Guo, Z.G. and Johnson, A.M. (1995) Genetic characterization of Toxoplasma gondii strains by random amplified polymorphic DNA polymerase chain reaction. Parasitology 111, 127-132. 

Joachim, A., Daugschies, A., Christensen, C.M., Bj0rn, H. and Nansen, P. (1997) Use of random amplified polymorphic DNA-polymerase chain reaction... 

Wu, Z., Nagano, I. and Takahashi, Y. (1998) The detection of Trichinella with polymerase chain reaction (PCR) primers constructed using sequences of random amplified polymorphic DNA (RAPD) or sequences of complementary DNA encoding excretory-secretory (E-S) glycoproteins. Parasitology 117, 173-183. 

The unique properties of oligonucleotides create crosslinking options that are far different from any other biological molecule. Nucleic acids are the only major class of macromolecule that can be specifically duplicated in vitro by enzymatic means. The addition of modified nucleoside triphosphates to an existing DNA strand by the action of polymerases or transferases allows addition of spacer arms or detection components at random or discrete sites along the chain. Alternatively, chemical methods that modify nucleotides at selected functional groups can be used to produce spacer arm derivatives or activated intermediates for subsequent coupling to other molecules. 

Kun E, Kirsten E, Ordahl CP (2002) Coenzymatic activity of randomly broken or intact double-stranded DNAs in auto and histone HI trans-poly(ADP-ribosylation), catalyzed by poly(ADP-ribose) polymerase (PARP I). J Biol Chem 277 39066-39069 Kun E, Kirsten E, Mendeleyev J, Ordahl CP (2004) Regulation of the enzymatic catalysis of poly(ADP-ribose) polymerase by dsDNA, polyamines, Mg2-F, Ca2-F, histones HI and H3, and ATP. Biochemistry 43 210-216... 

List of Abbreviations GABA, gamma-aminobutyric acid type A 5HT3, 5-hydroxytryptamine type 3 SDM, site-directed mutagenesis PCR, polymerase chain reaction TRCP, targeted random chimera production SDS, sodium dodecyl sulphate... 

The sequence neutrality for random stretches of double-stranded DNA makes uranyl ion a very useful reagent for examining contact regions in protein-DNA complexes. Such photo-footprinting studies have been carried out with the A-repressor/ORl [185], E. Coli RNA polymerase/deo Plpromoter [187] and transcription factor IIIA-ICR [188]. 

---