Alternative linear pathways

The equation medianRT = con + minlinEN ET + cycEN ET does not mean, that all reaction times are represented by this equation. There will be reaction times that will use a longer linear pathway linEN minlinEN. But the equation states that a prominent subset of reaction times uses minlinEN. How can this be proven  

If a larger subset uses minlinEN then this value should occur in the event-related potentials. 

How would a simulated distribution of reaction times look like if all obey the above equation. 

Altogether the relative constancy of linEN is still insufficiently secured. This can imply the existence of other cycEN and other search strategies of memory sets. 

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In a similar analysis of the case indicated by Fig. 3.16(a)(i) it can be shown that X is displaced out of the general molecular plane while y and z additionally describe an arc of 90°. However, the Xyz nuclei at all times remain in a plane that bisects the polyene system, so that the change is of the linear chele tropic type. Here the topology of the interactions on the orbitals of Xyz are, of course, identical to the alternative linear pathway in which X remains in the general molecular plane (cf. Fig. 3.18(a)), but the additional translational displacements on y and z does ensure a more efficient bonding contact between polyene and Xyz when the disrotatory mode is in operation. 

It is among the most capable of invertebrate anaerobes, the helminths and the marine bivalves, that we find the best examples of alternative fermentation pathways. Many of these have been reviewed several times elsewhere, so only a brief summary will be considered here. Current concepts view the organization of anaerobic metabolism as a series of linear, and loosely linked, pathways. The most important of these, aside from classical glucose — lactate fermentation (yielding 2 moles ATP per mole glucose) are summarized by Hochachka and Somero (1984) as follows (see chapter 2) ... 

Figure 12.2. Arrhenius plots for reactions with shift in rate control but no change in form of rate equation (schematic). Left shift to different step within same pathway right shift to alternative, parallel pathway. Dashed lines are linear extrapolations into respective other temperature regions (from Helfferich and Savage [14]).

Metabolic enzymes operate in the context of a metabolic network that must provide energy as well as the precursors of biomolecules. The topology of the network would be expected to influence the evolution of novel enzyme activities. Innovations that enhance a newly needed activity but compromise an original activity may not be tolerated in enzymes that produce metabolites required in many pathways. Innovations that compromise an original activity in linear pathways may be more harmful than innovations in dense parts of the metabolic network where diversion of flux through alternative pathways can allow production of critical metabolites even if a particular enzyme is temporarily compromised. 

Other alternative reaction pathways to AA or MAA via hydroformylation of 7-octenoic acid or the respective ester and consecutive oxidation of the formed aldehydic group may fail due to the poor accessibility of the C8 compound needed as starting material. This is unfortunate because recent development in the selective hydroformylation to linear aldehydes using sophisticated phosphite ligands [134,135] may enable such reaction sequence. 

Why is the linear pathway of the x33y task so long. What happens during this time A linear progression is not very plausible. What alternative courses are imaginable ... 

Several characterized NRPSs utilize alternative methods for chain termination. In some synthetases, the TE domain of the final module is replaced by an NAD(P)H-dependent reductase domain. Reduction of a peptidyl-S-PCP substrate through a two-electron reaction leads to the formation of a transient aldehyde, which is subsequently converted into a cyclic imine or hemiaminal through intramolecular cyclization. This two-electron reaction is utilized in the biosynthesis of nostocyclopeptides, the saframycins, ° and anthramycin. Alternatively, a four-electron reduction to the primary alcohol is observed in the biosynthesis of mycobacterial peptidolipids, linear gramicidin," " the myxalamides, lyngbyatoxin, " and myxochelin A 75,76 alternative four-electron reduction pathway involving aldehyde formation, transamination, and reduction to a primary amine occurs in the biosynthesis of myxochelin B. ... 

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