Correlation with Activity

Equilibrium Data Collection, DECHEMA, Frankfurt, Germany, 1979) have reported several volumes of data that have been correlated with activity-coefficient equations. 

Methylation of histones is correlated with activation and repression of gene transcription. 

Xu G, Zhang W, Ma MK, McLeod FIL (2002) Human carboxylesterase 2 is commonly expressed in tumor tissue and is correlated with activation of irinotecan. Clin Cancer Res 8 2605-2611... 

Kwan-Lim G-E, Forsyth KP, Maizels RM Filarial-specific IgG4 response correlates with active Wuchereria ban-crofti infection. J Immunol 1990 145 4298-4305. 

Aconitase was first determined to be an Fe-S protein in 1972 by Kennedy, Rauner and Gawron (23). Chemical analyses of inactive enzyme gave values of 2 Fe and 3 S /protein of 66,000 daltons. The observed molar relaxivity of water protons by this preparation of aconitase was 473 M s l (25). This value was an order of magnitude lower than measured in the earlier preparation of Villafranca and Mildvan (21) and much closer to that of Fe-S proteins (26). One mole of Fe + per mole of protein was taken up by the enzyme upon activation in the presence of cysteine and ascorbate, or lost upon inactivation in the presence of the iron chelator ferrozine (27). Gawron s group also demonstrated a correlation between loss of one Fe and loss of enzyme activity, as well as the protection afforded by citrate against both losses. However, the presence of an Fe-S cluster in aconitase remained for the moment a curiosity, in particular because of the unusual Fe/S= stoichiometries. The essential Fe that is correlated with activity continued to be interpreted in terms of the "ferrous-wheel" model. 

HATs catalyze the post-translational acetylation of amino-terminal lysine tails of core histones, which results in disruption of the repressive chromatin folding and an increased DNA accessibility to regulatory proteins. The level of histone acetylation is highly controlled and balanced by the activity of histone deacetylases (HDACs), the opponents of HATs. Generally, acetylation is correlated with activation and deacetylation with repression of gene expression. Therefore, the dynamic equilibrium of these proteins represents a key mechanism of gene regulation. 

Wang Q, Worland PJ, Clark JL, Carlson BA, Sausville EA (1995) Apoptosis in 7-hydroxystaurosporine-treated T lymphoblasts correlates with activation of cy-clin-dependent kinases 1 and 2. Cell Growth Differ 6 927-936 Wang J, Walsh K (1996) Resistance to apoptosis conferred by CDK inhibiors during myocyte differentiation. Science 273 359-361 Wang Q, Fan S, Eastman A, Worland PJ, Sausville EA, O Connor PM (1996) UCN-01 a potent abrogator of G1 checkpoint function in cancer cells with disrupted P53. J Natl Cancer Inst 88 956-965... 

In the case of visual hallucinations, similar studies have shown that these are correlated with activity in the occipital lobes (Ffytche et al., 1998). The localisation of activity was associated with the specific phenomenological characteristics of the hallucination for example hallucinations of unfamiliar faces were found by Kanwisher et al. (1997) to be accompanied by increased activity in the left middle fusiform gyrus, an area related to unfamiliar face stimuli. As with auditory hallucinations, increased activity in the affected area preceded the onset of the hallucination. 

Limitations of semm levels pharmacokinetic parameters determined in blood are not closely indicative of the situation in the central compartment (here the CNS) serum levels are not correlated with activity (pharmacodynamics) in general, only the mother molecule is assayed although its metabolites may be active or toxic the relationship between concentration (PK) and activity (PD) is often complex assays of free forms would be more pertinent. 

The earlier values for Er and Eqx are retained in the subsequent discussion of the sensitizing and desensitizing properties of dyes to conform to the earlier literature. The general conclusions would not be changed by using Lenhart s values, except for the quantitative correlation with activation energies of sensitization referred to in Section X. 

Taft s constants were used as molecular descriptors to correlate with activation energy and kinetic rates, respectively. They were used because they describe the inductive effects of the substituents in aliphatic compounds. Taft s constant showed a poor correlation (r2 = 0.68) for aliphatic compounds however, the correlation between activation energy and Taft s constant was... 

In an influential early investigation, correlation of biocatalytic activity data of aerobic and anaerobic whole-cell biocatalysis with solvent properties resulted in the strongest correlation for the partition coefficient log P, whereas both Hildebrand s solubility parameter 6 and the dielectric constant e showed either a weak correlation with activity data or none at all (Laane, 1985,1987) (Figure 12.2). 

In one of the most extensive studies of metal chloride catalysts,1 twenty of them supported on carbon were investigated, and a correlation was proposed between their activity and the electron affinity of the metal cation divided by the metal valence. Since the correlation consisted of two straight lines, it cannot be used predictively. However, electron affinity is necessarily a one-electron process, whereas hydrochlorination is more likely to be a two-electron process, involving the 2ir electrons of ethyne. Because many of the cations investigated are divalent, standard electrode potential was suggested1 as a more suitable parameter for correlating with activity. 

NAA levels in DLPFC of patients correlated with activation of DLPFC, TL and inferior parietal cortex during Wisconsin Card Sort Test no correlation in the ACC and STG 4 NAA/Cre in Flippo region and DLPFC of patients no differences in the thalamus, putamen, occipital cortex, ACC, posterior cingulate, prefrontal WM or STG 4 NAA/Cre and NAA/CFIO in Flippo region and DLPFC of patients, no differences found in the thalamus, putamen,... 

By combining the techniques of XPS and XAS, insights into the electronic structure of the dehydrogenation catalysts V Oy/alumina have been observed, and, by correlation with activity data, a greater understanding of the dehydrogenation mechanism and subsequent coke formation, was possible. 

Drug class System correlated with activity ... 

Activity does not correlate with activation energy. This indicates that microheterogeneity cannot by explained in terms of differences in the ability of individual molecules to reduce the activation energy. Thus other sources of heterogeneity must exist. 

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