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Molecular activity

Temperature The degree of molecular activity in a body high activity gives a high temperature, low activity a low temperature. The degree of activity is based on the assumption that absolute zero has no molecular movement at all. The following are some specific temperatures ... [Pg.1480]

The turnover number of an enzyme, is a measure of its maximal catalytic activity, is defined as the number of substrate molecules converted into product per enzyme molecule per unit time when the enzyme is saturated with substrate. The turnover number is also referred to as the molecular activity of the enzyme. For the simple Michaelis-Menten reaction (14.9) under conditions of initial velocity measurements, Provided the concentration of... [Pg.438]

Dynamic equilibria occur frequently in chemical systems. Chemical processes reach a state of equilibrium if allowed to continue for a sufficient time. Nevertheless, molecular activity always goes on after equilibrium has been reached. The following example, illustrated schematically in Figure 2-9. should help you grasp this important idea. [Pg.73]

In an ideal pure preparation of Na,K-ATPase from outer renal medulla, the al subunit forms 65 70% of the total protein and the molar ratio of a to is 1 1, corresponding to a mass ratio of about 3 1 [1,5]. Functionally the preparation should be fully active in the sense that each a/ unit binds ATP, Pj, cations and the inhibitors vanadate and ouabain. The molecular activity should be close to a maximum value of 7 000-8 000 Pj/min. The highest reported binding capacities for ATP and phosphate are in the range 5-6 nmol/mg protein and close to one ligand per otjS unit [29], when fractions with maximum specific activities of Na,K-ATPase [40 50 pmo Pj/min mg protein) are selected for assay. [Pg.3]

When combined with the isolation and reactivity studies of the patterned aminosilica (7), the increased activity of the patterned catalysts provide further evidence that the patterning technique developed allows for the synthesis of aminosilicas which behave like isolated, single-site materials (although a true single site nature has not been proven). As the olefin polymerization catalysts supported by the patterned materials show a marked improvement over those materials supported on traditional aminosilicas, these patterned materials should be able to improve supported small molecular catalysis as well. Future improvements in catalysis with immobilized molecular active sites could be realized if this methodology is adopted to prepare new catalysts with isolated, well-defined, single-site active centers. [Pg.277]

In the IPCM calculations, the molecule is contained inside a cavity within the polarizable continuum, the size of which is determined by a suitable computed isodensity surface. The size of this cavity corresponds to the molecular volume allowing a simple, yet effective evaluation of the molecular activation volume, which is not based on semi-empirical models, but also does not allow a direct comparison with experimental data as the second solvation sphere is almost completely absent. The volume difference between the precursor complex Be(H20)4(H20)]2+ and the transition structure [Be(H20)5]2+, viz., —4.5A3, represents the activation volume of the reaction. This value can be compared with the value of —6.1 A3 calculated for the corresponding water exchange reaction around Li+, for which we concluded the operation of a limiting associative mechanism. In the present case, both the nature of [Be(H20)5]2+ and the activation volume clearly indicate the operation of an associative interchange mechanism (156). [Pg.536]

Selectivity in catalytic oxidation/reduction and acid-base reactions has been a long-term challenge in the catalysis field. While it has been recognized that the control of molecular activation and reaction intermediates is critical in achieving high selectivity, this issue has not been adequately addressed and is a serious challenge to the field. [Pg.229]

Absolute zero. Minus 273°C or minus 460 or 0°K or Kelvin, the scale used in theoretical physics and chemistry. Absolute zero is the theoretical temperature at which all molecular activity ceases. In practical terms, the lowest reachable temperature is about 1°K. [Pg.385]

Attempts have also been made to exploit the relatively high molecular activity of cod trypsin at low temperatures by incorporating the enzyme into herring "fermentations that proceed at 10°C. The preparation of brine-fermented round herring (matjes) is limited to certain seasons because of the balance of digestive enzymes in the fish at this time. Other studies have indicated that proteinases are important components in matje fermentation 41),... [Pg.71]

But remember that in an earUer chapter it was noted that there is an analogy between the immune system and NP metaboUsm. Both are mechanisms evolved to generate chemical diversity to overcome the low probability of any one product having appropriate bio molecular activity. [Pg.233]

Rehberg, E., B. Kelder, E.G. Hoal, and S. Pestka, Specific molecular activities of recombinant and hybrid leukocyte interferons. J Biol Chem, 1982. 257(19) 11497-502. [Pg.174]

Once a chemical is in systemic circulation, the next concern is how rapidly it is cleared from the body. Under the assumption of steady-state exposure, the clearance rate drives the steady-state concentration in the blood and other tissues, which in turn will help determine what types of specific molecular activity can be expected. Chemicals are processed through the liver, where a variety of biotransformation reactions occur, for instance, making the chemical more water soluble or tagging it for active transport. The chemical can then be actively or passively partitioned for excretion based largely on the physicochemical properties of the parent compound and the resulting metabolites. Whole animal pharmacokinetic studies can be carried out to determine partitioning, metabolic fate, and routes and extent of excretion, but these studies are extremely laborious and expensive, and are often difficult to extrapolate to humans. To complement these studies, and in some cases to replace them, physiologically based pharmacokinetic (PBPK) models can be constructed [32, 33]. These are typically compartment-based models that are parameterized for particular... [Pg.25]

Nevertheless the fact that nitrogen pentoxide in presence of nitrogen peroxide is decomposed by blue light, and indeed, the whole of photochemistry, shows that there is nothing impossible in principle about the radiation theory, and examples in which infra-red radiation plays some part in molecular activation may yet be discovered. [Pg.146]

Here Et is the total enzyme, namely, the free enzyme E plus enzyme-substrate complex ES. The equation holds only at substrate saturation, that is, when the substrate concentration is high enough that essentially all of the enzyme has been converted into the intermediate ES. The process is first order in enzyme but is zero order in substrate. The rate constant k is a measure of the speed at which the enzyme operates. When the concentration [E]t is given in moles per liter of active sites (actual molar concentration multiplied by the number of active sites per mole) the constant k is known as the turnover number, the molecular activity, or kcat. The symbol fccat is also used in place of k in Eq. 9-6 for complex rate expressions in which fccat cannot represent a single rate constant but is an algebraic expression that contains a number of different constants. [Pg.457]

The action of catalase is very fast, almost 104 times faster than that of peroxidases. The molecular activity per catalytic center is about 2 x 105 s-1. [Pg.852]

Oxophenarsine 597s 5-Oxoproline, 551s, 662s Oxosteroid isomerase 526, 696 molecular activity 696 A5-3-Oxosteroid isomerase... [Pg.927]

The interesting suggestion has been made (61) that the unusually high molecular activity of extracellular /3-lactamases (Table II) may possibly compensate for the dilution of the secreted enzyme in the growth medium. [Pg.31]

Most of the properties of RNase Ti are summarized in Tables II and IV. It is a very acidic protein, active between pH 4 and 8.5 it is most active at pH 7.5 for RNA digestion (12) and at pH 7.2 for the hydrolysis of guanosine 2, 3 -cyclic phosphate (18). The purified enzyme possesses a specific activity of about 1.6 X 10 units/mg of protein. The molecular activity (standard units/jumole enzyme) has not been determined for the cleavage of a definite dinucleoside monophosphate such as GpC or for the hydrolysis of guanosine 2, 3 -cyclic phosphate. [Pg.213]


See other pages where Molecular activity is mentioned: [Pg.161]    [Pg.528]    [Pg.68]    [Pg.91]    [Pg.284]    [Pg.3]    [Pg.3]    [Pg.152]    [Pg.407]    [Pg.254]    [Pg.142]    [Pg.231]    [Pg.68]    [Pg.27]    [Pg.197]    [Pg.355]    [Pg.706]    [Pg.280]    [Pg.115]    [Pg.693]    [Pg.696]    [Pg.910]    [Pg.915]    [Pg.924]    [Pg.78]    [Pg.224]    [Pg.97]    [Pg.360]    [Pg.101]   
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See also in sourсe #XX -- [ Pg.457 ]

See also in sourсe #XX -- [ Pg.457 ]

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Actinides, molecular activation

Activated molecular collision

Activation energy molecular orientation

Activation molecular basis

Activation molecular determination

Activation of Molecular Oxygen by Cytochrome

Activation of molecular hydrogen

Activation of molecular hydrogen by homogenous

Activation volume molecular dynamics

Activators of Molecular Oxygen

Active molecular orbitals, MCSCF methods

Activity Molecular structures

Activity coefficient models molecular parameters

Activity coefficient of molecular solutes

Activity coefficients of molecular species

Activity of Alkaline Earth-Modified Mesoporous Molecular Sieves

Activity single molecular species

Antioxidative activity molecular mass

Applications, molecular electronics active elements

Arrhenius activation energy molecular interpretation

Atomisation kinetics when molecular adsorption is activated

Biological activity, molecular weight

C-H Activation Using Molecular Oxygen

Carbon activation molecular sieve

Catalase molecular activity

Chemokine receptor activation, molecular

Direct molecular dynamics, complete active

Direct molecular dynamics, complete active space self-consistent field

Direct molecular dynamics, complete active technique

Discovery of Highly Active Molecular Catalysts for Ethylene Polymerization

Enamine, Iminium, and Singly Occupied Molecular Orbital Activation

Enzymatic activity dual output molecular probe

Enzyme molecular activity

Ethylene polymerizations, highly active molecular catalysts

FUGACITY AND ACTIVITY OF MOLECULAR SPECIES IN SUPERCRITICAL FLUIDS

Hexokinase, active site molecular model

Hydrogenation mechanisms molecular hydrogen, activation

Infrared active bond molecular vibrations

Molecular Activation and Deactivation

Molecular Oxygen Binding and Activation Oxidation Catalysis

Molecular activation

Molecular activation energy

Molecular activation fluids

Molecular activation high temperature reaction

Molecular activation microwave reactions

Molecular activation, trivalent uranium

Molecular activation-limited rate constant

Molecular active components

Molecular activity (turnover

Molecular activity Subject index

Molecular activity of enzymes

Molecular catalysts designing, with active transition metals

Molecular catalysts designing, with catalytically active species

Molecular catalytic activity

Molecular descriptors, used structure-activity

Molecular docking quantitative structure-activity relationship

Molecular electronics, electrically active

Molecular electronics, electrically active polymers

Molecular hydrogen, activation

Molecular hydrogen, activation routes

Molecular imaging, optically active

Molecular junctions active

Molecular mechanics nonlinear optical activity

Molecular modifications biological activity

Molecular neutron activation analysis

Molecular optical activity

Molecular optical activity types

Molecular orbital theory complete active space self-consistent field

Molecular properties active site structure

Molecular redox-active molecule

Molecular scaffolds, structure-activity

Molecular scaffolds, structure-activity relationships

Molecular similarity activity landscapes

Molecular solutes, activity

Molecular solutes, activity coefficients

Molecular transcription factor activation

Molecular vibration infrared active molecules

Molecular vibration, infrared active

Molecular weight activation temperature

Molecular-level activity

Molecular-screening activated carbon

Optical activity molecular basis

Optical activity molecular mechanics calculation

Oxosteroid isomerase molecular activity

Phillips catalysts, activation molecular models

Postulate of the activated molecular collision

Quantitative structure-activity comparative molecular field

Quantitative structure-activity molecular descriptors

Quantitative structure-activity relationship molecular descriptors

Quantitative structure-activity relationship molecular modeling

Quantitative structure-activity relationships molecular/quantum mechanics computer

Receptor activation, molecular processes

Redox active molecular orbital

Redox active molecular orbital RAMO)

Redox active molecular orbitals

Redox-active amino acids molecular structure

Reductive activation, of molecular oxygen

Singly occupied molecular orbital activation

Structure-activity methods molecular modification

Structure-activity relationships and molecular modeling

Structure-activity relationships molecular basis

Structure-activity relationships molecular biology

Structure-activity relationships molecular design

Structure-activity relationships molecular similarity, virtual screening

Synthetic vitamin molecular activities

The Activation of Molecular Oxygen

The Structural and Molecular Dynamics of Salt Activation

The molecular polarizability and optical activity tensors

Titanium silicate molecular sieves active sites

Transition State Theory Molecular Nature of the Activated Complex

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