Methods single-molecule catalysis

Most analytical methods employed to study elementary reactions and reaction intermediates provide information about ensembles of reactive molecules. However, for more than a decade now, it has been possible to monitor transformations of single molecules by means of fluorescence microscopy. This involves the labeling of at least one of the reactants with a fluorophore, which in the case of a catalytic reaction would be either the catalyst or the substrate. The visualization of a chemical reaction then relies on changes of the fluorescence induced by a transformation at the reactive center of a catalyst. Herten and coworkers present several case histories. The use of single-molecule spectroscopy and the way in which the methods developed in this field may give rise to potential single-molecule catalysis are described in Chapter 3. 

The inner core of microemulsion can dissolve water to form water core called water pool [1], Little water pools of microemulsion surrounded by the single molecule interface formed by surfactants and co-surfactants can form particles whose sizes are from tens to hundreds of A [2], In this paper, a microemulsion-based method, and the formation conditions and growth mechanism of nanosized nickel sulfide particles are reported. This research is the base of application of ultrafme NiS particles on catalysis and optics. 

Escherichia coli have also developed an elegant method to control enzyme catalysis that occurs by covalent modification of each subunit. In this latter reaction a single tyrosyl residue per subunit is adenylylated to produce a stable 5 -adenylyl-O-tyrosyl derivative. Recent NMR and fluorescence data will be reviewed concerning the nature of this adenylyl site and its spatial relationship to the metal ions at the catalytic site. The enzymes responsible for the covalent adenylylation reaction comprise a cascade system for amplifying the activation or inactivation of glutamine synthetase molecules (81). 

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