Reagent

About: Reagent is a research topic. Over the lifetime, 60091 publications have been published within this topic receiving 1234928 citations. The topic is also known as: reagens.

Paper partition chromatography of reducing sugars with benzidine as a spraying reagent.

Abstract: IN the course of investigations into the application of paper chromatography to the identification of reducing substances in urine it was found that, when ammoniacal silver nitrate was used as a developing reagent, urates, normally present in urine, produced a dark brown spot with an RF value of approximately 0·20. This spot, which generally ‘tails', tends to mask the spots produced by other reducing substances with RF values in the region of 0·20, namely, those of glucose, sorbose, arabinose and fructose.

Disulfide-Bond Cleavage and Formation in Proteins

Abstract: Disulfide bonds can be cleaved at an alkaline pH by treating a protein with excess of a reagent disulfide in the presence of catalytic amounts of thiol. The cleavage products are stable and can be isolated; they contain the mixed disulfide between the reagent and the exposed thiol groups of the protein. The extent of cleavage is readily controlled by the pH of the reaction, temperature, and the addition of urea. Disulfide bonds cleaved by the reaction can be re-formed by exposing the mixed disulfide of the protein to catalytic amounts of thiol. Specific side chains can be added on to the thiol groups in native proteins by treatment with a reagent disulfide alone.

Mild Silver‐Mediated Geminal Difluorination of Styrenes Using an Air‐ and Moisture‐Stable Fluoroiodane Reagent

Abstract: An air- and moisture-stable fluoroiodane in the presence of AgBF4 is suitable for selective geminal difluorination of styrenes under mild reaction conditions. One of the C=F bonds is formed by transfer of electrophilic fluorine from the hypervalent iodine reagent, while the other one arises from the tetrafluoroborate counterion of silver. Deuterium-isotope-labelling experiments and rearrangement of methyl styrene substrates suggest that the reaction proceeds through a phenonium ion intermediate.

An economical method for cell-free protein synthesis using glucose and nucleoside monophosphates.

Abstract: Cell-free protein synthesis reactions have not been seriously considered as a viable method for commercial protein production mainly because of high reagent costs and a lack of scalable technologies. Here we address the first issue by presenting a cell-free protein synthesis system with comparable protein yields that removes the most expensive substrates and lowers the cell-free reagent cost by over 75% (excluding extract, polymerase, and plasmid) while maintaining high energy levels. This system uses glucose as the energy source and nucleoside monophosphates (NMPs) in place of nucleoside triphosphates (NTPs) as the nucleotide source. High levels of nucleoside triphosphates are generated from the monophosphates within 20 min, and the subsequent energy charge is similar in reactions beginning with either NTPs or NMPs. Furthermore, significant levels (>0.2 mM) of all NTPs are still available at the end of a 3-h incubation, and the total nucleotide pool is stable throughout the reaction. The glucose/NMP reaction was scaled up to milliliter scale using a thin film approach. Significant yields of active protein were observed for two proteins of vastly different size: chloramphenicol acetyl transferase (CAT, 25 kDa) and beta-galactosidase (472 kDa). The glucose/NMP cell-free reaction system dramatically reduces reagent costs while supplying high protein yields.