Molecule coupling

Ligases (syniheiases). Enzymes catalysing the joining together of two molecules coupled with the hydrolysis of a pyrophosphate bond in ADP or a similar triphosphate. They include some carboxylases and many enzymes known as synthetases. 

Applications. Molecules couple to an electromagnetic field through their electric dipoles, so only those having a permanent dipole moment exhibit significant rotational spectra. For such species, microwave spectroscopy yields highly precise moments of inertia and details of centrifugal... 

Ligases catalyze the joining together of two molecules, coupled to the hydrolysis of a pyrophospho-ryl group in ATP or a similar nucleoside triphosphate. 

Ligases (synthetases) - catalyzing the condensation of 2 molecules coupled with the cleavage of a pyrophosphate bond of ATP or similar triphosphate. 

Methods for quantifying both the transcellular diffusion and concurrent metabolism of drugs and the unusual transcellular diffusion of membrane-interactive molecules coupled with the influence of protein binding are described in detail. To demonstrate the utility of cultured cell monolayers as a tool for basic science investigations, a subsection is devoted to the elucidation of rate-determining steps and factors in the passive diffusion of peptides across biological membranes. The chapter concludes with a discussion on the judicious use of in vitro cell monolayer results to predict in vivo results. 

The presence of unwanted carboxylate groups in macromolecules may be easily blocked by the use of a small amine-containing molecule coupled via the carbodiimide procedure (Chapter 3, Section 1). 

Hydroxyl molecule coupled to surface via urethane bond... 

Condensation of the carbonyl function with an amine from a second 1,2-diaminoethane molecule coupled with a repeat of the initial reaction sequence will lead to the cyclic product. It is of interest that this is one case in which the synthesis will also proceed in the absence of a metal ion. Starting from a mono-protonated salt of 1,2-diaminoethane in acetone, the metal-free condensation may proceed via a reaction such as [2.7], Once again, a hydrogen-bonding network may act as a template for the reaction and also serve to stabilize the product once it is formed. A revised synthesis of the metal-free ligand (61) has been published (Hay,... 

The second reason for the lower yields is the high reactivity of the intermediate. Two molecules of the alkynyl bromide react in a stepwise manner with the zirconacyclopentadiene. When one alkynyl halide molecule couples with the zirconacyclopentadiene, the intermediate bears a metalladienyne moiety (as in 50), as shown in Eq. 2.36... 

In the open molecule coupled to an external electron reservoir, which fixes the system chemical potential, they combine the minimum-energy responses in the system number of electrons and the remaining nuclear coordinates to a unit displacement of Qs. The associated MECs,... 

HIV is a typical member of the retrovirus family, in that it is an enveloped virus that carries RNA as its genetic information. The structure of HIV (Fig. 2) has been determined by electron microscopy. The viral membrane is acquired from the infected cell as the virus buds through the cell membrane. Inserted into the viral membrane are protein molecules coupled to carbohydrates (glycoproteins) which are essential for viral infectivity and probably also play a role in the... 

It is instructive to illustrate the use of Equations 5.19 and 5.29 using a simplistic 3-atom model calculation for water. Even though it is well established that the condensed phase structure of water is complicated and involves the coordinated motions of many molecules coupled through a constantly fluctuating hydrogen bond network, the fundamentals of the VPIE are represented reasonably well by the simplified model. 

Molecules Couplings Calculated value Experm. value... 

The induced motions in the surroundings are estimated by examining the effects of a systematic velocity v imposed on one of the molecules, called here the central molecule. The couples of the central molecule lead to JV, other molecules which move in response to the motion of the central molecule. Likewise, the Ni first order partners are coupled to N2 second order partners, and so on through a hierarchy of orders order / contains Nj molecules, coupled for the first time to the central molecule through a sequence of / couples. The induced velocity of each order is assumed to be a constant fraction s of the velocity of the preceding order. The formal expression for the force resisting the motion of the central molecule becomes therefore ... 

In Ref. [4] we have studied an intense chirped pulse excitation of a molecule coupled with a dissipative environment taking into account electronic coherence effects. We considered a two state electronic system with relaxation treated as diffusion on electronic potential energy surfaces with respect to the generalized coordinate a. We solved numerically equations for the density matrix of a molecular system under the action of chirped pulses of carrier frequency a> with temporal variation of phase [Pg.131]

---