Turn-over rates

Thus, although organophosphorus compounds like fenitrothion may be metabolized in aquatic organisms through oxidative desulfuration, side chain oxidation, hydrolytic cleavage of P-O-arryl linkage, as well as O-demethylation, the turn-over rate apparently is much lower than in mammals. 

This procedure is usually not viable for processes with low air turn-over rate and/or poor filtration. One key feature is that the humidifier "off" condition should approach a reasonable steady-state character. However, it may be unnecessary to achieve steady-state if first it is clearly shown that dust levels fall well below the PEL. 

In some processes, especially those with low air turn-over rate and poor filtration, it is unclear in the time allowable by process constraints that the PEL can be achieved. In other words, the process may not operate normally for more than two hours... 

These examples clearly show that the combination of modem methods and concepts of natural product biosynthesis and enzymology with effective techniques of chemical synthesis can help to solve challenging problems in the preparation of complex molecules. Rapidly evolving methods for the optimization of certain desirable characteristics of a particular enzyme (e.g., directed alteration of enzyme properties like substrate specificity, selectivity, turn-over rates, and stability) will continue to facilitate the design of desired enzyme reactivity [241]. Increasing interdisciplinary cooperation between chemists, biochemists, and biologists will thus be vital for the successful continuation and development of modem natural product research. 

Stranski-Krastanov mode). For many catalytic reactions the metal cluster s size and shape controls the turn-over rate of the reaction, resulting in a particular interest for the understanding of the cluster growth. Three processes are defined for the initial growth process the adsorption step, the diffusion step and the nucleation step. We will pay special attention to these three processes. 

C-atom on a global scale. However, the actual cycling and turn-over rates of carbon in biological systems within various micro-environments have to be considered short-circuited and much more rapid, as numerous radiocarbon labeling experiments show. Life processes also stimulate and regulate multiple subcycles of carbonate dissolution and reprecipitation (see Chapters 2.2 and 2.4). On the other hand, some carbon deposited in stable continental interiors (cratons) remains protected from dissolution (or oxidation) and recycling from the time of deposition billions (10 ) of years ago up to the present. 

Furthermore, one might try to explain the persistence of cultural divisions by the absence of some of the conditions for class consciousness discussed in 6.2.2. If, for instance, the turn-over rate of the work force is quite high, there may never be time to overcome the cultural prejudices and hostilities among the workers. This line of argument, while not implausible, forms a very weak reply to the objection. It says, essentially, that cultural divisions are not inherently stronger than class divisions. The former dominate the latter only under certain conditions, that may or may not obtain. Now there may be some who would argue that culture is invariably more important than class, but there is no need to accept this view in order to object to the Marxist view that the priority invariably is the other way around. 

A. The antimetabolite plays the role of a substrate If the antimetabolite is capable of undergoing the enzyme-catalyzed reaction with the resulting dissociation of the enzyme-antimetabolite complex into (abnormal) produces) and the free enzyme, then it may be considered an abnormal substrate, or substitute metabolite. As such, it will competitively interfere with the transformation of the normal metabolite the extent of such interference depends on the relative affinity of the antimetabolite for the enzyme as well as on the rate of its conversion and subsequent release by the enzyme (i.e., the turn-over rate of the enzyme-antimetabolite complex). In the extreme (but important) case when the affinity is very high and the turnover rate very low, such antimetabolites act, in effect, as potent enzyme inhibitors, rather than as substitute metabolites (see B.iii) below). In the majority of cases, those classical antimetabolites which are capable of undergoing the enzyme-catalyzed reaction, having affinities and conversion rates comparable to those of the corresponding normal metabolites, exert only a partial and temporary inhibition at those steps of the metabolic pathway in which they themselves are metabolized, and therefore, their effective action as metabolic inhibitors will depend on their inhibition of other targets and on subsequent metabolic events (see Section 2.3.). 

Several Pt-Au clusters stabilized by phosphine ligands have been shown to catalyse the H2-D2 equilibration (Hj + D2 - 2 HD) in heterogeneous conditions with turn-over rates for HD production comparable to those of activated Pt surfaces... 

Metabolic Turn-Over Rate and Cardiac Work. 17-7... 

In the mammalian system there are two constitutive NOS isoforms, neuronal (nNOS) and endothelial (eNOS), and one inducible NOS isoform (iNOS). All three isoenzymes are homo-dimers. Each monomer has a molecular weight ranging from 130,000 to 150,000 daltons containing four prosthetic groups FAD, FMN, H4B and heme. The turn-over rate of NO production for each monomer is 0.5-2 molecules per second. Since NO is hydrophobic (solubility in water is only 2.82 mM) and is somewhat lipophilic (Kow 6.5 at 37 °C), NO freely diffuses rapidly through the hydrophobic environment of cell membranes just like O2 and N2. In the aqueous phase of the cytoplasm, the diffusion coefficient of NO is 3.6xl0 5 cm 3s->. Biosynthesized within the cell, NO may react with a select few types of molecules... 

Bishop, Ch., Garner, W., Talbott, J.H. Pool size, turn-over rate, and rapidity of equilibration of injected isotopic uric acid in normal and pathological subjects. J. Clin. Invest. 30 879 (1951 a). Bishop, C., Rand, R., Talbott, J.H. The effect of Benemid on uric acid metabolism in one normal and one gonty subject. J. Qin. Invest. 30 889 (1951 b)... 

Specific activity, selectivity, turn-over rate, K -value of the biological recognition element... 

The content of BChl per R. rubrum chromatophore has been determined to 790 (12). From the present work the number of FoFi-ATPases per chromatophore (60 nm in diameter) can be calculated to 7. Furthermore, the turn-over of the FgFi-ATPase in R. rubrum chromatophores has been determined. The chromatophores showed a rate of ATP synthesis of 9 ATP (pmol BChl) l min"l, which corresponds to a turn-over for the enzyme of 17 ATP sec . Interestingly, the turn-over rate of ATP synthesis in rat liver mitochondria is similar, 16-27 ATP sec" (13,14). Turn-over rates for ATP hydrolysis in chromatophores was 2.0 ATP sec l in the absence of uncoupler and 7.0 in the presence of 1 pM FCCP. 

VoLWiLER, W., P. D. Goldsworthy, M. P. MacMartin, P. A. Wood, I. R. Mackay, and K. Fremont-Smith Biosynthestic determination with radioactive sulfur of turn-over rate of various plasma proteins in normal and cirrhotic man. J. din. Invest. 34, 1126—1146 (1955). 

Cardiac reserve volume, 1-6 Cardiac sarcounit, 8-23 Cardiac work and metabolic turn-over rate, 17-7 Cardiopulmonary resuscitation, see CPR... 

Mertz, H.J., 52-5, 52-7, 53-9 Merz, B., 49-21 Merzenich, M.M., 29 7 Metabolic turn over rate and cardiac work, 17 7 Metallic biomaterials, 38 1-38-19 implants manufacturing,... 

Fig. 6.4. Calculated and measured CO2 turn-over rates as a function of CO pressure (top left) ...

Introduction Dimensional Analysis of Physiological Function Invariant Numbers and Their Physiological Applications Comparative Analysis of the Mammalian Circulatory System Metabolic Turn-Over Rate and Cardiac Work Comparative Pulse Transmission Characteristics Optimal Design Features References... 

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