Consecutive cycle matrix

Figure 18-11 Possible catalytic cycle of cytochrome c oxidase at the cytochrome a3 - CuB site. The fully oxidized enzyme (O left center) receives four electrons consecutively from the cyt c —> CuA —> cyt a chain. In steps a and b both heme a and CuB, as well as the CuA center and cyt a3/ are reduced to give the fully reduced enzyme (R). In the very fast step c the cyt a3 heme becomes oxygenated and in step d is converted to a peroxide with oxidation of both the Fe and Cu. Intermediate P was formerly thought to be a peroxide but is now thought to contain ferryl iron and an organic radical. This radical is reduced by the third electron in step/ to give the ferryl form F, with Cu2+ participating in the oxidation. The fourth electron reduces CuB again (step g) allowing reduction to the hydroxy form H in step h. Protonation to form H20 (step ) completes the cycle which utilizes 4 e + 4 H+ + 02 to form 2 H20. Not shown is the additional pumping of 4 H+ across the membrane from the matrix to the intermembrane space.

A simple interpolation technique, based on the values of just the consecutive R matrices, is easily implemented. If we assume that for the first few cycles in the SCF process each R matrix will overshoot the target which lies somewhere between these successive cycles we can write... 

In a later study, bis-NHC ruthenium-alkylidene complex was activated under compressive strain [87] (Fig. 16). In order to initiate Ru-mediated polymerisation of norbomene in solid state, polymer catalyst (34 kg mol ) and a norbomene monomer were incorporated in a high molecular weight poly(tetrahydrofuran) (pTHF) matrix (Mn=170 kDa, PDI=1.3) which provided the physical cross-linking through the crystalline domains and allowed macroscopic forces to be transferred to the metal-ligand bonds. Consecutive compressions showed that up to 25% of norbomene monomer was polymerised after five loading cycles. 

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