State ratio

Year United States Canada North America South b America World Wodd/United States ratio... 

Because of the differing rates of the component reactions, the CNO cycle modifies the initial composition of the material, which typically has O > C > N, making more 14N (and more 13C relative to 12C) at the expense of carbon and (at the higher temperatures) oxygen. Thus in H-buming zones the CN mixture is rapidly modified, and the CNO mixture somewhat more slowly modified, to reach steady-state ratios,4 e.g. at T = 3 x 107 K the steady-state percentages of CNO isotopes, compared to Solar-System values, are as follows ... 

The steady-state ratio of nitrogen dioxide concentration to nitric acid can be readily found to be... 

PHOSPHORYLASE KINASE PHOSPHORYLASE PHOSPHATASE PHOSPHORYLATION STATE RATIO 6-Phosphoryl-IMP,... 

The distinction between simple and induced diastereoselectivity is not affected, and the concepts are useful. However, characterization of simple diastereoselectivity by stating ratios of groups of diastereomers can be troublesome. 

The coenzyme NADP+ differs from NAD+ only by the presence of a phosphate group (-P04=)on one of the ribose units (Figure 13.4). This seemingly small change in structure allows NADP+ to interact with NADP+-specific enzymes that have unique roles in the cell. For example, the steady-state ratio of NADP+/NADPH in the cytosol of hepato-cytes is approximately 0.1, which favors the use of NADPH in reductive biosynthetic reactions. This contrasts with the high ratio of NAD7NADH (approximately 1000 in the cytosol of hepatocytes), which favors an oxidative role for NAD+. This section summarizes some important NADP+ or NADPH-specific functions. 

Various measures of the phosphorylating potential of the adenylate system within cells have been proposed. One measure is the product [ATP] / [ADP][P ], which will be called the phosphorylation state ratio... 

Photosynthetic phosphorylation of protein side chains 79 substrate level 775, 800 Phosphorylation, photosynthetic. See Photosynthetic phosphorylation Phosphorylation reactions 303 Phosphorylation state ratio definition of 303 O-Phosphoserine 610s Phosphoserine 545 Phosphothreonine 545 Phosphotransferase system bacterial 419,420 Phosphotransferases 637... 

Roundworms (Nematoda) 24 Rp (phosphorylation state ratio) 303 rRNA (ribosomal RNA) 5, 230,233s RS notation... 

Now consider Eq. 17-42, step a, the ADP- and P -requiring oxidation of glyceraldehyde 3-phosphate (Fig. 15-6). Experimental measurements indicated that this reaction is also at equilibrium in the cytoplasm. In one series of experiments the measured phosphorylation state ratio [ATP]/[ADP] [PJ was 709, while the ratio [3-phosphoglycerate]/[glyceraldehyde 3-phosphate] was 55.5. The overall equilibrium constant for Eq. 17-42a is given by Eq. 17-44. That calculated from known equilibrium constants is 60. 

From these data Krebs and Veech concluded that the oxidation state of the NAD system is determined largely by the phosphorylation state ratio of the adenylate system.169 If the ATP level is high the equilibrium in Eq. 17-42a will be reached at a higher [NAD+]/[NADH] ratio and lactate may be oxidized to pyruvate to adjust the [lactate]/[pyruvate] ratio. 

Just as with the pentose phosphate cycle, an exact reversal of the glycolysis sequence (Eq. 17-53) is precluded on thermodynamic grounds. Even at very high values of the phosphorylation state ratio Rp, the reaction ... 

An interesting experiment is to allow oxidative phosphorylation to proceed until the mitochondria reach state 4 and to measure the phosphorylation state ratio Rp, which equals the value of [ATP] / [ADP][PJ that is attained. This mass action ratio, which has also been called the "phosphorylation ratio" or "phosphorylation potential" (see Chapter 6 and Eq. 6-29), often reaches values greater than 104-105 M 1 in the cytosol.164 An extrapolated value for a zero rate of ATP hydrolysis of log Rf) = 6.9 was estimated. This corresponds (Eq. 6-29) to an increase in group transfer potential (AG of hydrolysis of ATP) of 39 kj/mol. It follows that the overall value of AG for oxidation of NADH in the coupled electron transport chain is less negative than is AG. If synthesis of three molecules of ATP is coupled to electron transport, the system should reach an equilibrium when Rp = 106 4 at 25°C, the difference in AG and AG being 3RT In Rp = 3 x 5.708 x 6.4 = 110 kj mol-1. This value of Rp is, within experimental error, the same as the maximum value observed.165 There apparently is an almost true equilibrium among NADH, 02 and the adenylate system if the P/O ratio is 3. 

However, if the electron transport between 3-hydroxybutyrate and cytochrome b562 is tightly coupled to the synthesis of one molecule of ATP, the observed potential of the carrier will be determined not only by the imposed potential E of the equilibrating system but also by the phosphorylation state ratio of the adenylate system (Eq. 18-7). Here AG atp is the group transfer potential (-AG of hydrolysis) of ATP at pH 7 (Table 6-6), and n is the number of electrons passing through the chain required to synthesize one ATP. In the upper part of the equation n is the number of electrons required to reduce the carrier, namely one in the case of cytochrome b562. 

The relative poor distributions observed with ZnCl2 and A1C13 are due in part to the small steric requirements of these Lewis acids, and in part to the fact that they accelerate C—C coupling so much that the steady state ratio of [4PN] to [3PN] is significantly less than the equilibrium ratio. This is particularly true of A1C13, with which significant amounts of ESN are formed (Section V,B,2). Note that under these conditions the simple treatment used to obtain Eq. (38) no longer applies, and both forward and reverse rate constants in steps 5, 6, 14, and 13 must be explicitly taken into account. 

It is clear from Equations 40 and 41 that the steady state ratio... 

Diffusion in the interstitial space is closely related to the volume fraction of space that is available to fluid and solute transport in tissues. The volume fraction of tumor interstitial fluid space varies from 15% in human gliomas up to 60% in a rat fibrosarcoma 4956 (Jain, 1987). The available volume fraction (KAV) of solutes is a measure of the steady state ratio of drag concentrations between tissues and the plasma (Krol et al., 1999). Thus, drug and gene delivery can be significantly improved through increasing KAV. In ex vivo experiments, KAV determines the ratio of concentrations between tissues and external solutions at the equilibrium state. KAV has been studied extensively in normal tissues but poorly in tumor tissues (Table 20.1) (Krol el al., 1999). KAV depends on the size of solutes and the dependence is determined by both the size and the connectedness of pores (Yuan et al., 2001). 

Figure 11.19(b) plots the steady state ratio of the viscosities of suspensions of spherical particles in Newtonian liquids, /iv, to the viscosity of the Newtonian fluid, /y. It was constructed by Thomas (79) using the data of a number of investigators. A variety of uniform-sized particles having diameters of 1 —4(X) pm were used. They included PS and... 

From the above, we can define the 0(1) steady-state ratios kr = HrjS/HfatS, kc = HCta/Htr,s, and kv = HVtS/HtrjS, and the scaled energy flows Ufa = Htr/Htr,a, W = fJr/i7rjS, uc = Hc/HCyS, and uv = Hv/HVyS. We also define... 

Ljgand Ground state e (cm-1) 7 State ratio AH (calM-1) AS (eu)... 

Figure 7 Polarized IR absorption spectra and their ratio measured 100 ps after photolysis of Mb13CO in D20. The left axis corresponds to the photolysis-induced absorbance changes, AA1- (thick lines) and AA11 (thin lines) the right axis corresponds to their ratio AA /AA11 (open circles). The ratio is plotted where the absorbance exceeds 25% of its maximum and has been corrected for fractional photolysis. The dashed lines correspond to the average A- and B-state ratios. The A- and B-state spectra were collected at 10.8% and 20% photolysis of Mb13CO, respectively. The background and hot band contributions to the B-state spectra have been removed. (Adapted from Ref. 51.)...

Product Vibrational State Ratios for the Reactions F + H2, D2, HD at Room Temperature [343]... 

Table II. Concentrations of Actinides and Dissolved Organic Carbon and Pu Oxidation State Ratios in Filtered Lake Water(11)...

The final states may be mixed with other orbitals and can be used to determine the coordination environment of an element in a compound, its electron density and oxidation state. The intensity can be used to accurately determine relative oxidation state ratios. Furthermore, XANES can be used to determine relative amounts of species by linear combination of individual compounds. In recent years, the codes for XANES calculation (especially John Rehr s FEFF code), have significantly improved and it can be expected that theoretical models of compounds will be accurately determined by XANES measurement and calculation in the future. 

Prolonged irradiation did not change the equihbrium steady-state ratio cis to trans isomers. 

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