Se complexes

Walker, J. E., 1992. The NADH ubiquinone oxidoreducta.se (Complex I) of respiratory chains. Quarterly Reviews of Biophysics 25 253-324. 

Wefss, H., Friedrich, T, Hofliaus, G., and Preis, D., 1991. The respiratory-chain NADH dehydrogena.se (Complex I) of mitochondria. European Journal of Biochemistry 197 563—576. 

S- and P-donor ligands. The complexes [(YPPh2 CH PPh2Y)2Fe] (Y = S or Se) are prepared by treating (Ph2PY)2CH with Bu"Li, followed by addition of an Fe" halogeno-complex anion. The complexes are both tetrahedral and the Se complex is the first example of tetrahedral co-ordination of Se to Fe". ... 

Ph2PY)2CH2 with Bu"Li followed by addition of metal halogeno-complex anions. Both compounds are tetrahedral and the Se complex is the first example of a tetrahedral [CoSe ] core. The tetrahedral [Co(S2AsMe2)2] ° and [Co(WOS3)2] "" " have been reported, the latter having only co-ordinated sulphur atoms. 

The Se complex, Zn(SeAr")2, is made by an analogous procedure from 2,4,6-tri-tert-bytylbenzeneselenol9 (1.03 g, 3.16 mmol) and Zn[N(SiMe3)2]2 (0.66 g, 1.71 mmol) to give a white precipitate (0.6 g). More product can be recovered from the mother liquor by adding light petroleum (20 mL) and refluxing for 2-3 h followed by filtration. The combined yield is 0.8 g (1.12 mmol, 72% based on Zn). 

The proposed mechanism for this reaction involves the initial coordination of styrene oxide to Tbt(Tip)Sn=Se followed by nucleophilic attack of a second Tbt(Tip)Sn=Se molecule on the less substituted carbon with the formation of cis- and trans-195. Alternatively, the unimolecular cyclization of the initial styrene oxide-Tbt(Tip)Sn=Se complex leads to the formation of compound 196 as a minor product (Scheme 10). 

Se(VI), total Se Complexed with 2,3 diaminonapthalene with EDTA-sodium fluoride Spectrofluorometry 0.4ng [292]... 

McFarlane and White (37) have noted that dimethylsulfoxide will replace Me2S and Me2Se when [(Me2L)2PtCl2] (L = S, Se) complexes are dissolved in DMSO according to Reactions 4 and 5. 

The ditelluride complex is a centrosymmetric dimer [177] and the Yb is tetrahedrally bonded to two Cp ligands and to the Te - ion. The structure of Se complex [178] has a linear Se-Yb-Se bridge (170.1°) with two Cp Yb units mutually staggered and the compound is seven coordinate. The structure of Ce complex [180] shows a rare example of Ce-S dative bond with Ce-S distances of 3.058 and 3.072 A. 

The n,pp value is less than the true n because throughout most of the velocity curve, the ES and SE complexes contribute to a substantial portion of the observed velocity. (For example, at u = 0.366 ES + SE account for 29.2% of the total enzyme while SES accounts for only 22%.) If a were much smaller (e.g., 0.02), then most of the enzyme will be present as either E or SES and tiapp would approach 2-... 

Step 4 of Figure 29.12 Oxidative Decarboxylation The transformation of a-ketoglutarate to succinyl CoA in step 4 is a multistep process just like the transformation of pyruvate to acetyl CoA that we saw in Figure 29.11. In both cases, an cv-keto acid loses CO2 and is oxidized to a thioester in a series of steps catalyzed by a multienzyme dehydrogena.se complex. As in the conversion of pyruvate to acetyl CoA, the reaction involves an initial nucleophilic addition reaction to a-ketoglutarate by thiamin diphosphate ylide, followed by decarboxylation, reaction with lipoamide, elimination of TPP ylide, and finally a transesterification of the dihydrolipoamide thioester with coenzyme A. 

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