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Substrate P (substrate + p)

Distribution by Scientific Domains

Chemistry	50%

Selected Abstracts

Effects of 100 GHz radiation on alkaline phosphatase activity and antigen,antibody interaction,

BIOELECTROMAGNETICS, Issue 3 2009
A. Homenko
Abstract Equipment that generates microwave radiation (MWR) spanning the frequency range of 300 MHz,100 GHz is becoming more common. While MWR lacks sufficient energy to break chemical bonds, the disagreement as to whether MWR exposure is detrimental to cellular dysfunction may be difficult to clarify using complex systems such as whole animals, cells, or cell extracts. Recently, the high frequency range of terahertz (THz) radiation has been explored and sources of radiation and its detectors have been developed. THz radiation is associated with the frequency interval from 100 GHz to 20 THz and constitutes the next frontier in imaging science and technology. In the present study, we investigated the effect of radiation in the low frequency THz range (100 GHz) on two defined molecular interactions. First, the interaction of soluble or immobilized calf alkaline phosphatase with the substrate p -nitrophenylphosphate and second, the interaction between an antibody (mouse monoclonal anti-DNP) and its antigen (DNP). Irradiation of enzyme either prior to addition of substrate or during the enzymatic reaction resulted in small but significant reductions in enzyme activity. These differences were not observed if the enzyme had previously been immobilized onto plastic microwells. Exposure of immobilized antigen to radiation did not influence the ability of the antigen to interact with antibody. However, irradiation appeared to decrease the stability of previously formed antigen,antibody complexes. Our data suggest that 100 GHz radiation can induce small but statistically significant alterations in the characteristics of these two types of biomolecular interactions. Bioelectromagnetics 30:167,175, 2009. © 2008 Wiley-Liss, Inc. [source]

Cloning, recombinant production, crystallization and preliminary X-ray diffraction analysis of a family 101 glycoside hydrolase from Streptococcus pneumoniae

ACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 2 2009
Katie J. Gregg
Streptococcus pneumoniae is a serious human pathogen that is responsible for a wide range of diseases including pneumonia, meningitis, septicaemia and otitis media. The full virulence of this bacterium is reliant on carbohydrate processing and metabolism, as revealed by biochemical and genetic studies. One carbohydrate-processing enzyme is a family 101 glycoside hydrolase (SpGH101) that is responsible for catalyzing the liberation of galactosyl ,1,3- N -acetyl- d -galactosamine (Gal,1,3GalNAc) ,-linked to serine or threonine residues of mucin-type glycoproteins. The 124,kDa catalytic module of this enzyme (SpGH101CM) was cloned and overproduced in Escherichia coli and purified. Crystals were obtained in space group P21 and diffracted to 2.0,Å resolution, with unit-cell parameters a = 81.86, b = 88.91, c = 88.77,Å, , = 112.46°. SpGH101CM also qualitatively displayed good activity towards the synthetic substrate p -nitrophenyl-2-acetamido-2-deoxy-3- O -(,- d -galactopyranosyl)-,- d -galactopyranoside, which is consistent with the classification of this enzyme as an endo-,- N- acetylgalactosaminidase. [source]

Synthesis and Reactivity of Ru(NHC)(dppp)(CO)H2 and Ru(NHC)(dppp)(CO)HF Complexes: C,H and C,F Activation

EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 13 2009
Steven P. Reade
Abstract The hydrido fluorido ruthenium(II) complex [Ru(PPh3)(dppp)(CO)HF] [1, dppp = 1,4-bis(diphenylphosphanyl)propane], which forms upon reaction of [Ru(PPh3)3(CO)HF] with dppp, reacts with IMes [1,3-bis(2,4,6-trimethylphenyl)imidazol-2-ylidene] to give the expected carbene-containing hydrido fluorido complex [Ru(IMes)(dppp)(CO)HF] (2), as well as the C,H activated species [Ru(IMes),(dppp)(CO)H] (3). The formation of the latter product results from the reaction of 2 with a base (IMes or Et3N). Displacement of PPh3 from [Ru(PPh3)(dppp)(CO)H2] by ICy (1,3-dicyclohexylimidazol-2-ylidene) yields [Ru(ICy)(dppp)(CO)H2] (7), which upon reaction with Et3N·3HF, gives [Ru(ICy)(dppp)(CO)HF] (8). Thermolysis of 7 with C6F6 at elevated temperature generates 8 and [Ru(ICy)(dppp)(CO)(C6F5)H] (9). The related fluoroaryl complexes [Ru(ICy)(dppp)(CO)(C6F4CF3)H] (10) and [Ru(ICy)(dppp)(CO)(C5F4N)H] (11) are formed upon the room temperature C,F activation of C6F5CF3 and C5F5N by 7, but also by C,H activation of the partially fluorinated substrates p -C6F4HCF3 and p -C5F4HN.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source]

Association of the SULT1A1 R213H polymorphism with colorectal cancer

CLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 9 2002
Chung Fai Wong
Summary 1.,Sulphotransferases are a superfamily of enzymes involved in both detoxification and bioactivation of endogenous and exogenous compounds. The arylsulphotransferase SULT1A1 has been implicated in a decreased activity and thermostability when the wild-type arginine at position 213 of the coding sequence is substituted by a histidine. SULT1A1 is the isoform primarily associated with the conversion of dietary N -OH arylamines to DNA binding adducts and is therefore of interest to determine whether this polymorphism is linked to colorectal cancer. 2.,Genotyping, using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis, was performed using DNA samples of healthy control subjects (n = 402) and patients with histologically proven colorectal cancer (n = 383). Both control and test populations possessed similar frequencies for the mutant allele (32.1 and 31%, respectively; P = 0.935). Results were not altered when age and gender were considered as potential confounders in a logistic regression analysis. 3.,Examination of the sulphonating ability of the two allozymes with respect to the substrates p -nitrophenol and paracetamol showed that the affinity and rate of sulphonation was unaffected by substitution of arginine to histidine at position 213 of the amino acid sequence. 4.,From this study, we conclude that the SULT1A1 R213H polymorphism is not linked with colorectal cancer in this elderly Australian population. [source]