S-acetonyl-CoA. A nonreactive analog of acetyl-CoA.

Rubenstein, P A; Dryer, Robert L.

doi:10.1016/s0021-9258(19)43913-6

Cited by 33 publications

(13 citation statements)

References 11 publications

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“…From the observed K¡ of 300 nM at pH 6.6 we can calculate an effective of the enethiolate of FAc(=S)CoA as being 620 pM, or 3.9 X 104 times less than the Rm for AcCoA. This value compares with the values of 70 nM and 9 µ for the negatively charged carboxymethyl-CoA (Bayer et al, 1981) and neutral acetonyl-CoA (Rubenstein & Dryer, 1980), respectively.…”

Section: Resultsmentioning

confidence: 83%

Citrate synthase stabilizes the enethiolate of acetyldithio-coenzyme A

Wlassics¹,

Anderson²

1989

Biochemistry

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Citrate synthase catalyzes the slow condensation of acetyldithio-CoA [Ac(= S)CoA] with oxalacetate to form thiocitrate [Wlassics, I.D., Stille, C., & Anderson, V.E. (1988) Biochim. Biophys. Acta 952, 269]. During the transient approach to steady state an observable amount of the dithioester absorbance disappears. The amplitude of the decrease in absorbance corresponds to 0.32, 0.03, and 0.02 enzyme equiv at pH 8.3, 7.5, and 6.6, respectively. The difference spectra from before and after the transient exhibit the dithioester lambda max at 306 nm. Acid quenching of a stiochiometric reaction between Ac(= S)CoA and citrate synthase following the transient quantitatively regenerates Ac(= S)CoA, indicating carbon-carbon bond formation had not yet occurred. The apparent first-order rate constant of the transient is independent of Ac(= S)CoA concentration and increases with decreasing pH, being 0.007, 0.016, and 0.04 s-1 at pH 8.3, 7.5, and 6.6, respectively. 2-Fluoroacetyldithio-CoA is a better inhibitor of citrate synthase, Ki = 300 nM, and substrate, Vmax = 2 X 10(-3) s-1, than Ac(= S)CoA. 1H NMR experiments indicate that citrate synthase catalyzes the exchange of the alpha-hydrogens of Ac(= S)CoA with turnover numbers of 0.13 and 0.54 s-1 at pD 7.9 and 7.2, respectively. Analysis of the proton and deuterium decoupled 13C NMR spectra of [2-13C]Ac(= S)CoA that has exchanged 37% of the alpha-hydrogens in the presence of citrate synthase indicates that the relative proportions of CH3, CH2D, CHD2, and CD3 were 0.29, 0.39, 0.25, and 0.07, respectively. This statistical distribution indicates each exchange event is independent. The data indicate that citrate synthase stabilizes the ionized form of Ac(= S)CoA by 5 kcal/mol relative to the un-ionized form, that the ionized dithioester is on the reaction pathway, and that below pH 8.3 the slow carbon-carbon bond forming reaction is responsible for the 10(6) decrease in Vmax caused by substituting sulfur for oxygen in the thioester carbonyl.

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Section: Resultsmentioning

confidence: 83%

Citrate synthase stabilizes the enethiolate of acetyldithio-coenzyme A

Wlassics¹,

Anderson²

1989

Biochemistry

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“…Several acyl-CoA analogs have been prepared previously which mimic the enol or enolate intermediate in reactions of enzymes that catalyze deprotonation of the methyl group of acetyl-CoA as part of catalysis, most notably citrate synthase. − However, few acyl-CoA analogs have been prepared that posess a tetrahedral center in place of the thioester carbonyl carbon, which may mimic the tetrahedral intermediate or transition state in the reactions of enzymes that catalyze acyltransfer. Exceptions are β-hydroxyalkyl-CoA thioethers, differing from the hemithioacetals described here in that they contain an additional methylene group between the sulfur atom and the hydroxymethine carbon. , …”

Section: Discussionmentioning

confidence: 63%

“…Exceptions are β-hydroxyalkyl-CoA thioethers, differing from the hemithioacetals described here in that they contain an additional methylene group between the sulfur atom and the hydroxymethine carbon. 30,31 Also recently reported have been sulfoxide and sulfone analogs 7 and secondary alcohol analogs, differing from the hemithioacetals by replacement of the sulfur atom with a methylene group. 27 Among these, only the secondary alcohol analogs have shown enhanced binding relative to the natural substrate for an enzyme catalyzing acyl transfer from a CoA ester.…”

Section: Discussionmentioning

confidence: 99%

Coenzyme A Hemithioacetals as Easily Prepared Inhibitors of CoA Ester-Utilizing Enzymes

1996

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Hemithioacetals are formed by reactions of coenzyme A (CoA) with aldehydes in aqueous solution. Equilibria for hemithioacetal formation with four commercially available aldehydes and rate constants for hemithioacetal dissociation have been studied. The hemithioacetals are viewed as acyl-CoA analogs having a tetrahedral center in place of the planar trigonal thioester carbonyl carbon. These compounds may serve as mimics of the tetrahedral intermediate or transition state in the reactions of acyl-CoA dependent acyltransferase enzymes. The hemithioacetal generated by reaction of CoA with formaldehyde is a poor inhibitor of chloramphenicol acetyltransferase, with a K i more than 6-fold higher than the K m for the substrate acetyl-CoA. The hemithioacetals formed by reaction of CoA with acetaldehyde and trifluroacetaldehyde are substantially better inhibitors, with K i values approximately 2.4-fold and 10-fold lower than the K m values for acetyl-CoA, respectively. The hemithioacetal formed by reaction of CoA with succinic semialdehyde inhibits succinic thiokinase, with a K i 4-fold lower than the K m for the substrate succinyl-CoA. The CoA hemithioacetals provide a novel readily accessible new class of acyl-CoA analogs for use in mechanistic and structural studies of CoA ester-utilizing enzymes.

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“…Despite major efforts toward the identification and development of such compounds, only two drug-like inhibitors for p300/CBP (KAT3a/b) and MOZ/MORF (KAT6a/b), respectively, were made available until to date. , Early approaches to this topic focused on bisubstrate mimics via covalent connection of the physiological cofactor to substrate peptides (acetonyl-CoA, Lys-CoA, and H3-CoA-20; Figure ). , While these compounds suffer from poor cell permeability and a complex structure, they exhibit potent and selective KAT inhibition. The concept was adopted for the generation of functionalized chemical probes mainly for the profiling of KAT substrates and for chemoproteomic applications .…”

Section: Introductionmentioning

confidence: 99%

“…34,35 Early approaches to this topic focused on bisubstrate mimics via covalent connection of the physiological cofactor to substrate peptides (acetonyl-CoA, Lys-CoA, and H3-CoA-20; Figure 1). 36,37 While these compounds suffer from poor cell permeability and a complex structure, they exhibit potent and selective KAT inhibition.…”

Section: ■ Introductionmentioning

confidence: 99%

Cofactor Analogues as Active Site Probes in Lysine Acetyltransferases

et al. 2019

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Lysine acetyltransferases (KATs, also termed histone acetyltransferases, HATs) catalyze the acetylation of substrate lysine residues by employing the cofactor acetyl-coenzyme A (AcCoA), thereby providing a dynamic control mechanism of protein function. Because of their major involvement in cell development and homeostasis, small-molecule modulators of KAT activity are urgently needed to assess their therapeutic potential and for probing their underlying biology. Recent advances in the field suggest that targeting the cofactor binding site represents a promising strategy for identifying potent and selective ligands. Here, we present the synthesis of two functional cofactor-based chemical probes and their usage as mechanistic tools in a broadly applicable assay platform. A fluorescence polarization (FP)-based binding assay was combined with biolayer interferometry competition analysis and a FP competition activity immunoassay to enable easy, reliable, and profound evaluation of ligands that target the KAT cofactor binding site.

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S-acetonyl-CoA. A nonreactive analog of acetyl-CoA.

Cited by 33 publications

References 11 publications

Citrate synthase stabilizes the enethiolate of acetyldithio-coenzyme A

Citrate synthase stabilizes the enethiolate of acetyldithio-coenzyme A

Coenzyme A Hemithioacetals as Easily Prepared Inhibitors of CoA Ester-Utilizing Enzymes

Cofactor Analogues as Active Site Probes in Lysine Acetyltransferases

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