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The isomerization energy, for example, for converting from a stable cis isomer to the less stable trans isomer is greater than for the reverse reaction, explaining why in the absence of isomerases or an outside energy source such as ultraviolet radiation a given cis isomer tends to be present in greater amounts than the trans isomer.
In chemistry, isomerization or isomerisation is the process in which a molecule, polyatomic ion or molecular fragment is transformed into an isomer with a different chemical structure. [1] Enolization is an example of isomerization, as is tautomerization .
The protein encoded by this gene is a dimeric enzyme that catalyzes the reversible isomerization of G6P and F6P. [12] [13] Since the reaction is reversible, its direction is determined by G6P and F6P concentrations. [9] glucose 6-phosphate ↔ fructose 6-phosphate. The protein has different functions inside and outside the cell.
For example, in the cyclic alcohol inositol (a six-fold alcohol of cyclohexane), the six-carbon cyclic backbone largely prevents the hydroxyl and the hydrogen on each carbon from switching places. Therefore, one has different configurational isomers depending on whether each hydroxyl is on "this side" or "the other side" of the ring's mean plane.
Example mechanism for alkyne zipper reaction. The 3-aminopropylamine anion attacks the same lesser-substituted carbon adjacent to the allene , removing a proton and catalyzing a similar process, where the electrons from the carbon-hydrogen bond move to form a triple-bond (an alkyne ).
Isomerization involves transforming a molecule so that it adopts a different structural conformation; proline isomerization plays an integral role in the modification of histone tails. [36] Fpr4 is the prolyl isomerase enzyme (PPIase) which converts the amino acid proline (P) on histones between the cis and trans conformations .
Skeletal isomerization is not normally encountered in the laboratory, but is the basis of large applications in oil refineries. In general, straight-chain alkanes are converted to branched isomers by heating in the presence of a catalyst. Examples include isomerisation of n-butane to isobutane and pentane to isopentane. Highly branched alkanes ...
The proteins that do this modification are called pseudouridine synthases (PUS) and are found in all kingdoms of life. Most research has been done on how PUS modify tRNA, so mechanisms involving snRNA, and mRNA are not clearly defined. PUS can vary on RNA specificity, structure, and isomerization mechanisms. The different structures of PUS are ...