Deb mechanism

Initial explanations in terms of an associative SN2-type reaction proved untenable, and the reaction is now thought to involve deprotonation of a co-ordinated amine (Fig. 2-17). This is the SN1 cb or Deb mechanism. The key step is the formation of the amide intermediate, [Co(NFl3)4(NH2)Cl]+, which undergoes halide loss to generate the reactive five-co-ordinate intermediate [Co(NH3)4(NH2)]2+ (2.2) (Fig. 2-18). 

B magnetic field strength Deb mechanism dec conjugate-base mechanism decomposition... 

ATP adenosine triphosphate Deb mechanism conjugate-base mechanism... 

Patri, M., Hande, V. R., Phadnis, S. and Deb, P. C. 2004. Radiation-grafted solid polymer electrolyte membrane thermal and mechanical properties of sulfonated fluormated ethylene propylene copolymer (FEP)-graft-acrylic acid membranes. Polymers for Advanced Technologies 15 622-627. 

Phadnis, S., Patri, M., Chandrasekhar, L. and Deb, P. C. 2005. Proton-exchange membranes via the grafting of styrene and acrylic acid onto fluorinated ethylene propylene copolymer by a preirradiation technique. III. Thermal and mechanical properties of the membranes and their sulfonated derivatives. Journal of Applied Polymer Science 97 1418-1425. 

Initial experiments with DEBS 1-TE showed that only the (2S)-isomer of methylmalonyl-CoA is used to generate both stereocenters (d and l) in the trike-tide lactone (Fig. 13) [36]. In follow-up experiments, DEBS 1-TE was incubated in the presence of starter unit, NADPH, and deuterium-labeled (2S)-methylmalo-nyl-CoA [42], Use of the isotopically labeled substrate allowed discrimination between possible mechanisms by which the synthase could generate two methyl stereochemistries from a precursor with a single methyl configuration (Fig. 14), because the deuterium labeling pattern in the resulting lactone was characteristic... 

M. T. Marron, Energies, Energy Differences and Mechanisms of Internal Motions, in The Force Concept in Chemistry (B. M. Deb, ed.). Van Nostrand-Reinhold, New York, 1981. 

Of the many metaheuristics available, evolutionary algorithms (EAs) have become very popular because of their ease of implementation and high effectiveness. EAs are based on an emulation of the natural selection mechanism (Goldberg, 1989). EAs are particularly suitable for solving multi-objective problems because of their ability to handle a set of solutions in a simultaneous manner, and their capability to deal with problems of different types, without requiring any specific problem-domain information (e.g., derivatives) (Deb, 2001). 

That [OH] appears in the rate equation shows it has a rate-determining role. However, this is not because [OH] attacks the metal centre but rather because it deprotonates a coordinated NH3 ligand. Steps 25.39-25.41 show the conjugate-base mechanism Deb or SnIc mechanism). A pre-equilibrium is first established, followed by loss of X to give the reactive amido species 25.1, and, finally, formation of the product in a fast step. 

Since the PKS (polyketide synthase) gene cluster for actinorhodin (act), an antibiotic produced by Streptomyces coelicolor[ 109], was cloned, more than 20 different gene clusters encoding polyketide biosynthetic enzymes have been isolated from various organisms, mostly actinomycetes, and characterized [98, 100]. Bacterial PKSs are classified into two broad types based on gene organization and biosynthetic mechanisms [98, 100, 102]. In modular PKSs (or type I), discrete multifunctional enzymes control the sequential addition of thioester units and their subsequent modification to produce macrocyclic compounds (or complex polyketides). Type I PKSs are exemplified by 6-deoxyerythronolide B synthase (DEBS), which catalyzes the formation of the macrolactone portion of erythromycin A, an antibiotic produced by Saccharopolyspora erythraea. There are 7 different active-site domains in DEBS, but a given module contains only 3 to 6 active sites. Three domains, acyl carrier protein (ACP), acyltransferase (AT), and P-ketoacyl-ACP synthase (KS), constitute a minimum module. Some modules contain additional domains for reduction of p-carbons, e.g., P-ketoacyl-ACP reductase (KR), dehydratase (DH), and enoyl reductase (ER). The thioesterase-cyclase (TE) protein is present only at the end of module 6. 

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