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Crystalline solids and molecular solids are two opposite extreme cases of materials that exhibit substantially different transport mechanisms. While in atomic solids transport is intra-molecular, also known as band transport, in molecular solids the transport is inter-molecular, also known as hopping transport.
Intramolecular reactions, especially ones leading to the formation of 5- and 6-membered rings, are rapid compared to an analogous intermolecular process. This is largely a consequence of the reduced entropic cost for reaching the transition state of ring formation and the absence of significant strain associated with formation of rings of these ...
Ligation is complicated by the fact that the reaction can involve both inter- and intra-molecular reactions, but the desired ligation products in many ligation reactions (e.g. ligating a DNA fragment into a vector) needed first to be inter-molecular, i.e. between two different DNA molecules, followed by an intra-molecular reaction to seal and ...
In nonpolar solvents contact ion pairs with very high association constants are formed; [3] [4] in the gas phase the association energies of e.g. alkali halides reach up to 200 kJ/mol. [5] The Bjerrum or the Fuoss equation describe ion pair association as function of the ion charges zA and zB and the dielectric constant ε of the medium; a ...
The sodium–potassium pump (a type of P-type ATPase) is found in many cell (plasma) membranes and is an example of primary active transport.Powered by ATP, the pump moves sodium and potassium ions in opposite directions, each against its concentration gradient.
This approach is widely applicable to long-range ground-state intramolecular electron transfer, electron transfer in biology, and electron transfer in conducting materials. It also typically controls the rate of charge separation in the excited-state photochemical application described in Figure 2 and related problems.
The nucleophilic lysine residue is commonly targeted site in protein bioconjugation, typically through amine-reactive N-hydroxysuccinimidyl (NHS) esters. [3] To obtain optimal number of deprotonated lysine residues, the pH of the aqueous solution must be below the pKa of the lysine ammonium group, which is around 10.5, so the typical pH of the reaction is about 8 and 9.
Chorismate mutase is an intramolecular transferase and it catalyzes the conversion of chorismate to prephenate, used as a precursor for L-tyrosine and L-phenylalanine in some plants and bacteria. This reaction is a Claisen rearrangement that can proceed with or without the isomerase, though the rate increases 10 6 fold in the presence of ...