In the absence of their acid/base residue, thioglycoligases require both an activated glycosyl donor to form the glycosyl-enzyme intermediate and an acceptor that is a strong nucleophile, capable of reacting without basic catalytic assistance (Fig. 1a); consequently, nucleophiles successfully assayed ...
2.0 x 10-2 mol/L NaOH(aq) d. 0.50 mol/L K2SO4(aq)Which is the stronger acid in the following pair?Which is the stronger acid in each pair?Which compound in each pair is the stronger acid? F_2CHCOOH, Cl_2CHCOOHWhat are all the strong acids and bases in chemistry?Which of the...
Which is the following reactions can be classified as a combination reaction? A) \ CuCO_3(s) \to CuO(s)+CO_2(g)\\ B) \ 4Fe(s) + 3O2(g) \to 2Fe_2O_3(s) \\ C) \ Mg(s)+2 AgNO_3(aq) \to Mg(NO_3)_2(aq)+2 Ag(s)\\ D) \ NaOH(aq)+HCI(aq) ...
Its high electronegativity means that it has a strong tendency to attract electrons, which contributes to its reactivity. When fluorine encounters other elements, it readily accepts electrons to form stable compounds. 4. Low Bond Dissociation Energy: - The bond dissociation energy of the F-F bond...
In CGI-58, Asn155 replaces the putative active site nucleophile. A large, primarily helical lid region (Pro180–Leu280) is inserted after strand β6 and covers the potential “active site.” An additional feature of the model is a long partly helical, partly unstructured region ranging from...
Here we bring extensive bioinformatics, in vivo and in vitro experimentation to compose a unified view of the biosynthesis of these widely distributed non-canonical amino acids that both derive by pyridoxal-mediated β-elimination of the activated O-phosphorylated substrates followed by β-addition of...
Because every nucleophile is potentially a base, and vice versa. If you have a reaction where it looks like you might get SN2 or E2, look closely first – is there any chance of a simple acid-base reaction? For instance, take NaOH plus an alkyl thiol, R–SH. Is it an SN2? Or ...
optionally in the presence of a suitable base (e.g. NaOH, triethylamine, pyridine or potassium carbonate) and an appropriate solvent (e.g. ether, water, dichloromethane, THF, tert-butyl methyl ether, or mixtures thereof). Compounds of formulae IV, VI, VIII, IX, X, M, XIII and XIV ...
Which of the following is considered a strong base? a. NH3 b. Be(OH)2 c. Mg(OH)2 d. Ba(OH)2 Consider these three anions. 1. Which one is the strongest base? 2. Which one the weakest base? 3. Which one is the nucleophile? What is the stronger base, OH^- or ...