نتایج جستجو برای: diethyl pyrocarbonate

تعداد نتایج: 5191  

Journal: :The Journal of biological chemistry 1990
D P Dumas F M Raushel

The pH rate profile for the hydrolysis of diethyl-p-nitrophenyl phosphate catalyzed by the phosphotriesterase from Pseudomonas diminuta shows a requirement for the deprotonation of an ionizable group for full catalytic activity. This functional group has an apparent pKa of 6.1 +/- 0.1 at 25 degrees C, delta Hion of 7.9 kcal/mol, and delta Sion of -1.4 cal/K.mol. The enzyme is not inactivated in...

2009
MAHMOOD AZARI ALAN WISEMAN

where [E]/[E], is fractional enzyme activity, and t is reaction time. The constants C and k were determined graphically (Defares & Sneddon, 1960). The results of the effect of diethyl pyrocarbonate on DEAE-cellulose column-chromatography fractions obtained from two samples of normal gastric mucosa and three samples of stomach adenocarcinoma are presented in summary form in Table I. It will be s...

Journal: :iranian journal of basic medical sciences 0
esfandiar heidarian department of biochemistry, medical school, ilam university of medical sciences, ilam, iran. bahram haghighi department of biochemistry, isfahan university of medical sciences, isfahan, iran.

objective(s) phosphatidate phosphohydrolase (pap) catalyzes the dephosphorylation of phosphatidic acid to yield pi and  diacylglycerol. two different forms of pap in rat hepatocyte have been reported. pap1 is located in cytosolic and microsomal fractions and participates in the synthesis of triacylglycerols, phosphatidylcholine, and phosphatidylethanolamine, whereas the other form of phosphatid...

Journal: :Plant physiology 1969
D P Weeks A Marcus

Isolation of polyribosomes from wheat embryos and corn root tips in the presence of diethyl pyrocarbonate showed this reagent to have a protective effect on polyribosome structure. In addition, the use of diethyl pyrocarbonate allowed initial homogenization to be performed under less stringent conditions than those normally employed for polyribosome isolation. The use of the reagent is however ...

Journal: :Biochemistry 1970
N J Leonard J J McDonald M E Reichmann

The use of diethyl pyrocarbonate as a nuclease inhibitor in the preparation of RNA of high molecular weight has prompted a study of the possible reactions of this compound with nucleic acid components under the conditions generally employed for providing inhibition. The first substrate investigated was adenine, which has been found to undergo ring opening with the formation of 5(4)-N-carbethoxy...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 1981
T P Burch M K Ticku

The effect of diethyl pyrocarbonate modification of histidine on the specific binding of [3H]diazepam and its enhancement with muscimol and (+/-)-pentobarbital was investigated. Diethyl pyrocarbonate treatment produced a dose-related inhibition of specific [3H]diazepam binding to rat brain membranes with a maximal inhibition of approximately 40% at 1 mM. Scatchard analysis of the binding data s...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 1987
D Mendel P B Dervan

Forms of the DNA double helix containing non-Watson-Crick base-pairing have been discovered recently based on x-ray diffraction analysis of quinoxaline antibiotic-oligonucleotide complexes. In an effort to find evidence for Hoogsteen base-pairing at quinoxaline-binding sites in solution, chemical "footprinting" (differential cleavage reactivity) of echinomycin bound to DNA restriction fragments...

Journal: :Nucleic acids research 1986
P M Scholten A Nordheim

Two palindromic DNA sequences were analyzed with respect to their chemical reactivities with diethyl pyrocarbonate. In negatively supercoiled plasmid templates enhanced N7 carbethoxylation was found with individual purines located in presumptive single-stranded loops of DNA cruciform structures. No enhanced reactivity at these positions was observed in linear, relaxed or low superhelical densit...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 1985
W Herr

Purine residues located within regions of DNA that have the potential to form left-handed Z-helical structures are modified preferentially by diethyl pyrocarbonate; this hyperreactivity is dependent on the degree of negative superhelicity of the circular DNA molecules. As negative superhelical density increases, guanosines in a 32-base-pair alternating G-C sequence and adenosines (but not guano...

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