Association/recombination

Reactions in a condensed phase are never isolated but under strong influence of the surrounding solvent molecules. The solvent will modify the interaction between the reactants, and it can act as an energy source or sink. Under such conditions the state-to-state dynamics described above cannot be studied, and the focus is then turned to the evaluation of the rate constant k(T) for elementary reactions. The elementary reactions in a solvent include both unimolecular and bimolecular reactions as in the gas phase and, in addition, bimolecular association/recombination reactions. That is, an elementary reaction of the type A + BC —> ABC, which can take place because the products may not fly apart as they do in the gas phase. This happens when the products are not able to escape from the solvent cage and the ABC molecule is stabilized due to energy transfer to the solvent.4 Note that one sometimes distinguishes between association as an outcome of a bimolecular reaction and recombination as the inverse of unimolecular fragmentation. 

Solvents may create the so-called cage effect, where the separation of products may be impeded, leading to a high probability of association/recombination. 

Transformation-associated recombination frani -activation response region Trani-activator of transcription... 

Adsorption followed by a surface dissociation step is the analogue of the oxidative addition reaction we have met earlier. Associative recombination reactions become favoured when the adatom energies become destabilized, i.e. to the right of the periodic system, when the d-valence electrons have become highly occupied. The associative recombination reaction followed by desorption is the analogue of the reductive elimination reaction. 

Chi WK, Ku CH, Chang CC (1994) Two-step cell disruption for the extraction of membrane-associated recombinant protein from Saccharomyces cerevisiae. Ann NY Acad Sci 721(1) 365-373... 

The question is, which role collision play in a BEC. The atoms are exposed to a laser field which excites them into higher electronic states. In collisions between excited atoms and ground state atoms the excitation energy can be transferred either into excitation energy of the other atom or into translational energy. The latter case will increase the velocity of atoms which then cannot be kept by the trapping potential and leave the trap. Another possibility is the associative recombination of a collision pair (see Fig. 9.17 and Sect. 9.1.6), where a stable dimer molecule is formed which, however, cannot be kept in the magnetic trap because its spin is different from that of the atoms. 

Debache K, Krope C, Schiitz CA et al (2011) Vaccination of mice with chitosan nanogel-associated recombinant NcPDI against challenge infection with Neospora caninum. Parasite Inununol 33 81-94... 

Kouprina,N., and Larionov, V. (2008) Selective isolation of genomic loci from complex genomes by transformation-associated recombination cloning in the yeast Saccharomyces cerevisiae, Nat Protoc. 3, 371-377. 

Kouprina N, Annab L, Graves J et al (1998) Functional copies of a human gene can be direcdy isolated by transformation-associated recombination cloning with a small 3 end target sequence. Proc Natl Acad Sci USA 95 4469 474... 

Leem SH, Noskov VN, Park JE et al (2003) Optimum conditions for selective isolation of genes from complex genomes by transformation-associated recombination cloning. Nucleic Acids Res 31 e29... 

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