DOSEN PROFIL LENGKAP

depolymerization reactions. Epimerization can be spontaneous (generally a slow process), or catalysed by enzymes, e.g. the epimerization between the sugars N-acetylglucosamine...

of ring opening occurs and the ketose is protonated. An example of epimerization is found in the Calvin cycle when D-ribulose-5-phosphate is converted...

L, et al. (March 2024). "Structural and mechanistic basis for RiPP epimerization by a radical SAM enzyme". Nature Chemical Biology. 20 (3): 382–391....

into 3-ketoses, etcetera. The enediol is also an intermediate for the epimerization of an aldose or ketose. The reactions are usually base catalyzed, but...

neosamine C (D-niosamine) in neamine biosynthesis, but with an additional epimerization step required to account for the presence of the epimeric neosamine...

Hall SD (March–April 1992). "Metabolic inversion of (R)-ibuprofen. Epimerization and hydrolysis of ibuprofenyl-coenzyme A". Drug Metabolism and Disposition...

presence of an acidic center between two carbonyl groups allows for easy epimerization at the chiral center under basic conditions. To select for one of the...

(S,R) is soluble. The precipitation of the (R,R) product drives the epimerization equilibrium reaction to form this as the major product. There are other...

the liver by 6β-hydroxylation, 3α- and 3β-oxidation, 5β-reduction, 17-epimerization, and conjugation among other reactions. Unlike methyltestosterone, owing...

condensing into the tripeptide, the amino acid L-valine must undergo epimerization to become D-valine. The condensed tripeptide is named...

well-known trans isomer. Formation of cis-THC could take place in process of epimerization associated with acid-catalyzed cyclization of CBD to THC. It has similar...

Wolfgang; Kühlein, Klaus; Börner, Armin (2011-03-02). "Studies on the epimerization of diastereomeric lactides". Tetrahedron Letters. 52 (9): 1027–1030...

dehydroxylated and epimerized to first component of the gentamicin C complex, gentamicin C2a which then undergoes an epimerization by GenB2 and then a...

domain. Modification is accomplished by the ketoreductase (KR) and epimerization (E) domains. Finally, the growing peptides are linked by condensation...

acid racemization during coupling is also of vital importance to avoid epimerization in the final peptide product.[citation needed] Amide bond formation...

the stereogenic center attached to the nitrile and phenyl groups easily epimerizes if the manufacturer does not store the compound correctly. Amygdalin is...

Ortz; Trinidad De Torres (2003). "Kinetics of amino acid racemization (epimerization) in the dentine of fossil and modern bear teeth". International Journal...

exposure to heat in alkaline pH conditions, 10 to 15% of the parent LSD epimerized to iso-LSD. Under acidic conditions, less than 5% of the LSD was converted...

forming oxazolidines and thiazolidine, respectively. Epimerization: Sometimes an E-domain epimerizes the innermost amino acid of the peptide chain into...

Since the threo isomers are energetically favored, it is easy to epimerize out any of the undesired erythro isomers. The drug that contains only...

determined that DMP could oxidize N-protected-amino alcohols, without epimerization (unlike most other oxidants, including Swern oxidation). These protected...

Saccomano NA, Thadeio PF, Volkmann RA (1996). "Posttranslational amino acid epimerization: enzyme-catalyzed isomerization of amino acid residues in peptide chains"...

l-lysergic acid derivatives, as compared with the natural d-lysergic acid. Epimerization at the C(8) position gives the isolysergic acid or iso-LSD derivatives...

stereoisomer into another. For example, racemization (as in SN1 reactions), epimerization (as in interconversion of D-glucose and D-mannose in Lobry de Bruyn–Van...

would be the formation of symmetrical acid anhydrides, racemization and epimerization and the cyclization to oxazolinones or - especially for dipeptides -...

epigallocatechin gallate (EGCG). In a high temperature environment, an epimerization change is likely to occur, because heating results in the conversion...

easily be converted to isomenthone and vice versa via a reversible epimerization reaction via an enol intermediate, which changes the direction of optical...

in the colon produces the secondary bile acid, hyodeoxycholic acid. Epimerization of the 7-hydroxyl to the β-position is found in ω-muricholic acid (also...

8-dephosphorylation (LmbK), guanosine diphosphate attachment at position 1 (LmbO), 4-epimerization (LmbM), 6-oxidation (LmbL), amination (LmbS), imine reduction (LmbZ)...

been isolated as a single enantiomer. Given the different rates of epimerization that occur at different pH levels, it was determined that there would...

of differential rate equations: Base-promoted epoxide isomerization Epimerization Racemization Tautomerization Linkage isomerism IUPAC, Compendium of...

4 D-amino acids, formed by epimerization of the activated L-amino acids. Modules 2, 4 and 5 each contain an epimerization (E) domain which catalyzes this...

ISBN 978-3-88763-075-1. Schänzer W, Opfermann G, Donike M (November 1992). "17-Epimerization of 17 alpha-methyl anabolic steroids in humans: metabolism and synthesis...

moiety to a mesylhydrazone, allowing for purification of 10 without epimerization at the C8 center. This mesylhydrazone group could then be fully removed...

l-lysergic acid derivatives, as compared with the natural d-lysergic acid. Epimerization at the C(8) position gives the isolysergic acid or iso-LSD derivatives...

vancomycin, additional modification domains are present, such as the epimerization (E) domain, which isomerizes the amino acid from one stereochemistry...

Although epimerization was historically an issue in the synthesis of 2,5-DKPs, several mild methods have been developed recently that avoid epimerization. 2...

co-workers leveraged the Riley Oxidation to attain the trans-glyoxal. Epimerization of the alpha hydrogen led to cis-glyoxal, which spontaneously underwent...

either. In particular, chiral α-aminoaldehydes do not react well due to epimerization and because amino groups can be easily transformed to their corresponding...

1016/S0899-9007(97)83035-3. PMID 9263278. Subirós-Funosas AE, Albericio F (2013). "Low-epimerization Peptide Bond Formation with Oxyma Pure: Preparation of Z-L-Phg-Val-OMe"...

rearrangement reactions. A similar reagent but moistened induces hydrolysis or epimerization reactions. On alumina, ferric chloride has been shown to accelerate...

glucose disposal. Exogenous DCI may act to bypass defective normal epimerization of myo-inositol to DCI associated with insulin resistance and at least...

tetramer found in Caragana sinica (Chinese : Jin Que-gen). Acid-catalyzed epimerization of kobophenol A to carasinol B can be performed in vitro. Shu Na; Zhou...

presence of CoA, ATP and Mg+2. (S)-profen does not form the thioester. Epimerization (Racemization): The enzyme epimerase 2-arylpropionic-CoA changes the...

Aldol condensation. Several examples are shown below: Elimination: Epimerization of penicillin derivatives, catalyzed by DBN: Aldol condensation: The...

This enzyme from the bacterium Mycobacterium smegmatis participates in epimerization of trans,octacis-decaprenylphospho-beta-D-ribofuranose to trans...

and magnolia. In racemic mixtures the odor is floral and citrus, while epimerized mixtures exhibit a dense buttery-floral odor with odor recognition thresholds...

dehydration mechanisms L-Ribulose 5-phosphate 4-epimerase catalyzes the epimerization of L-ribulose 5-phosphate to D-xylulose 5-phosphate by retro-aldol cleavage...

For clarity, the stereocenter on the enolate has been epimerized; in reality, the opposite diastereoface of the aldehyde would have been attacked....

structure of the catalyst and adjacent quaternary ring group minimizes epimerization of this stereocenter. Oxidation by the active dioxirane catalyst takes...

Due to the reversibility of the reaction and the tendency for easy epimerization of the nitro-substituted carbon atom (among a number of factors), the...

important metabolic pathway in metabolism of RBG, whereas for rats, 3-O-epimerization is the main metabolic pathway in liver microsomes, generating a different...

adenylation domain (A), a peptidyl carrier protein domain (PCP), an epimerization domain (E), and a condensation domain (C). Cyclization is accomplished...

After multiple enzyme reaction steps, which include phosphorylation, epimerization, dehydration, and keto-reduction reactions, valienol, an important core...

(Z)-(cis)-isomers as zinc complex. The inactive (Z)-(cis)-isomers may be epimerized to the more thermodynamically favored (E)-(trans)-isomers via reflux in...

; Silverman, Richard B. (2025). "Kinetically Controlled aza-Michael/Epimerization Cascade Enables a Scalable Total Synthesis of Putative (+)-Fumigaclavine...

It has been shown to inhibit acetylcholinesterase. Acid-catalyzed epimerization of kobophenol A to carasinol B can be performed in vitro. Sung, Sang...

solution unaffected and is recycled back to the racemic mixture by epimerization with hydrochloric acid in toluene. This process is known as RRR synthesis...

to epimerization. For example, the end product of cocaine biosynthesis contains an axial C2-carbomethoxy moiety which readily undergoes epimerization to...

(VePesid, VP16) Lung cancer, testicular cancer A group obtained through epimerization at position 4 directly interacts with toposoimerase 2, preventing DNA...

name of this enzyme class is GDP-L-fucose:NADP+ 4-oxidoreductase (3,5-epimerizing). This enzyme is also called GDP-4-keto-6-deoxy-D-mannose-3,5-epimerase-4-reductase...

improved synthesis of aziridine-2,3-dicarboxylates via azido alcohols—epimerization studies". Tetrahedron: Asymmetry. 14 (21): 3301–3312. doi:10.1016/j...

incubating the product in an aqueous solution at pH 8, in order to make the epimerization at C11 still occur. Like every saxitoxin, the gonyautoxins are neurotoxins...

cyclization of the resulting 6-oxo intermediate, creating manojirimycin (MJ). Epimerization of MJ at the C2 position yields the nojirimycin isomer. Nojirimycin...

the ethylamine bridge and further elaboration (including an arduous epimerization of the highlighted stereocenter) established the so-called "Gates Intermediate...

J. E.; Torres, T. D. (2003). "Kinetics of amino acid racemization (epimerization) in the dentine of fossil and modern bear teeth". International Journal...

2-dihydroxyindolizidine. Finally, an 8-hydroxyl group is introduced through epimerization at C-8a to yield swainsonine. Schneider et al. have suggested that oxidation...

glycol by hNth1 and hNeil1 is modulated by base pairing and cis-trans epimerization". DNA Repair. 5 (4): 444–54. doi:10.1016/j.dnarep.2005.12.004. PMID 16446124...

catalysts formed large amounts of dimeric and oligomeric products. An epimerization risk under the cross-metathesis reaction conditions. The process chemistry...

undergo an unusual degree of post-translational modification including epimerization of leucine and tryptophan, tryptophan bromination, amidation of the...

additional charges. It is C3 of D-ribulose 5-phosphate which undergoes this epimerization, forming D-xylulose 5-phosphate. The mechanism is clearly demonstrated...

some instances, an epimerization domain is necessary in those modules where L-amino acid monomers are to be incorporated and epimerized to D-amino acids...

"Understanding nature's strategies for enzyme-catalyzed racemization and epimerization". Acc. Chem. Res. 35 (4): 237–246. doi:10.1021/ar000056y. PMID 11955052...

N-acetylglucosamine-6-P. This becomes N-acetylmannosamine-6-P through epimerization, which reacts with phosphoenolpyruvate producing N-acetylneuraminic-9-P...

Susan M.; Jeffrey L. Bada (June 1988). "Aspartame decomposition and epimerization in the diketopiperazine and dipeptide products as a function of pH and...

the use of NMI as the base, due to its low pKa(H2O) of 7, is that the epimerization of labile stereogenic centers is minimized. The reaction by-products...

araD encodes L-ribulose-5-phosphate 4-epimerase, which catalyses epimerization between L-ribulose 5-phosphate and D-xylulose-5-phosphate. Both L-ribulose...

Alkaline ester hydrolysis of 19 to carboxylic acid 20 was accompanied by epimerization at C14. Compound 20 was known from earlier strychnine degradation studies...

N-acetyl-D-galactosamine (GalNAc). Some of these GlcA residues may be epimerized into L-iduronic acid (IdoA) at which point the resulting glycosaminoglycan...

methionine (SAM). Finally NovS reduces the 4 position again to achieve epimerization of that position from the starting glucose-1-phosphate using NADH. Rings...

and 40 °C. Evidence suggests that the elimination is syn; however, epimerization at both carbon and selenium (both of which are stereogenic) may occur...

(February 2020). "Synthesis of rare sugar isomers through site-selective epimerization". Nature. 578 (7795): 403–408. Bibcode:2020Natur.578..403W. doi:10...

configuration at the α-position is less predictable, especially in cases when epimerization can occur. On the basis of steric approach control, the new α-substituent...

transformation was utilized as a mild way to methylenate the C1 ketone without epimerization of C8a or base-catalyzed rearrangement which the gibberellin scaffold...

the trans isomer is the thermodynamically favoured racemer, although epimerization may be needed to convert the cis isomer to the needed trans isomer....

the kinetics of an intermediate step. Alternately, the halohydrin can epimerize due to the basic nature of the reaction conditions prior to the SN2 reaction...

establishes the stereochemistry and isomeric nature of the sugars by epimerization between gluconic and mannonic acids and synthesizes glucose, fructose...

polymerization model, the Langevin equation, and the activation-polymerization-epimerization-depolymerization (APED) model to imitate potential prebiotic conditions...

1016/S0021-9258(18)82242-6. PMID 7683683. Stindl A, Keller U (August 1994). "Epimerization of the D-valine portion in the biosynthesis of actinomycin D". Biochemistry...

the observed stereospecificity of the process. Whether the initial epimerization of trans substrates occurs via a one- or two-center process is unclear...

models for the transmission of chiral asymmetry are polymerization, epimerization or copolymerization. Experimental work has demonstrated that enantiomerically...

Haveren, Jacco; Van Es, Daan S. (2013). "Synthesis of Isoidide through Epimerization of Isosorbide using Ruthenium on Carbon". ChemSusChem. 6 (4): 693–700...

4649. PMID 11352583. Yeh WK, Ghag SK, Queener SW (1992). "Enzymes for epimerization of isopenicillin N, ring expansion of penicillin N, and 3'-hydroxylation...

reaction of either enantiomer is necessarily higher than the barrier to epimerization, resulting in a kinetic well containing the racemate. This is equivalent...

changing the orientation of the hydroxyl group on the 4th carbon through epimerization. This helps replenish the UDP-glucose used in step 2. Finally, glucose-1-phosphate...

hypobromite anion; hence, potassium bromide is used as an additive. No epimerization of α-stereogenic centers in carbonyl-containing products takes place...

was in their feces. The isomerization of brasofensine did not involve epimerization at 2-position of the tropane ring, but rather involved the E/Z-isomerization...

that it is aminated and does not undergo 3-OH deoxygenation or C-5 epimerization. GDP-perosamine synthase is a PLP-dependent enzyme that transfers a...

"Intrashell variations in amino acid concentrations and isoleucine epimerization ratios in fossil Hiatella arctica". Geology. 11 (9): 509–513. Bibcode:1983Geo...

Schmidtchen A, Yoshida K, Fransson LA (October 1994). "Patterns of uronosyl epimerization and 4-/6-O-sulphation in chondroitin/dermatan sulphate from decorin...

periphery adjacent to the chromophore system turned out to be prone to epimerization. This required a separation of diastereomers in an advanced stage of...

unstable, as the molecules may undergo reactions (known as racemization or epimerization respective to the type of stereoisomer pair involved) and become the...

mixture, it was postulated that the enzyme performs the C5-epimerization prior to the C3-epimerization. However, GDP-D-altrose was recently found as a reaction...

(4). The Jones oxidation leads to the enone of the finished product. Epimerization of the beta-methyl group also occurred during this step. Thus, completing...

acids activated on the enzyme as aminoacyl adenylates. Unlike PKS, epimerization, N-methylation, and heterocycle formation occurs in the NRPS enzyme...

position and forming UDP-6’-deoxy-5-6-ene-GlcNAc. TunF then catalyzes the epimerization of the intermediate to UDP-6’-deoxy-5-6-ene-GalNAc, changing the 4’...

present that are responsible for modifications to the residues, such as epimerization domain (E) and N-methyltransferase domain (MT). The domain responsible...

diphosphate 2-deoxyglucose. Chemical synthesis, enzymic oxidation and epimerization". Biochimica et Biophysica Acta. 381 (2): 301–7. doi:10.1016/0304-4165(75)90236-6...

mechanism of aldose backbone rearrangement (C1–C2 transposition) during C2-epimerization catalyzed by molybdate ion. Serianni's early research centered on NMR-based...

gets loaded onto the conserved serine in the T domain, Epimerization (E) domain where it epimerizes L-amino acid to D-amino acid. Starting module GrsA loads...

solvent effects on chemical equilibrium can be seen in a study of the epimerization of chiral cyclopropylnitrile Grignard reagents.[non-primary source needed][non-primary...

electropositive metals, and do not spontaneously undergo allylic rearrangement or epimerization. Additionally, organosilanes are rarely toxic and their reactions can...

L'Annunziata, Juan González Iturbe, Luis A. Olivares Orozco (1977) "Microbial epimerization of myo-inositol to chiro-inositol in soil". Soil Science Society of...

glucose-1-phosphate feeds into glycolysis, while UDP-galactose undergoes epimerization to regenerate UDP-glucose. Galactose UDP galactose epimerase Uridine...

is possible to convert the endo isomer 5b to the exo isomer 5a by an epimerization process through the enol. The ketone groups are converted to oxime groups...

sugars metabolism. FEINGOLD DS, NEUFELD EF, HASSID WZ (1960). "The 4-epimerization and decarboxylation of uridine diphosphate D-glucuronic acid by extracts...

a wide variety of amidations, including peptides, with low risk of epimerization. CMDT has been successfully used at multikilogram scales to prepare...

often observed in reactions where radical rebound is rapid enough that epimerization does not happen. Barton, D.H.R; Csuha, E; Ozbalik, N (1990). "Functionalisation...

found in natural patellamide A are the D-epimers. It is proposed that epimerization of these amino acids occurs spontaneously. This was determined by comparison...

modifications onto the polytheonamide A and B precursor peptides, including 18 epimerizations. Polytheonamides are exceptionally large, as a single molecule is able...

sugars metabolism. FEINGOLD DS, NEUFELD EF, HASSID WZ (1960). "The 4-epimerization and decarboxylation of uridine diphosphate D-glucuronic acid by extracts...

diseases such as Necrotizing Fasciitis. Tyler TR, Leatherwood JM (1967). "Epimerization of disaccharides by enzyme preparations from Ruminococcus albus". Arch...

then attacks a SAM methyl group in the active site of EvaC. EvaD then epimerizes molecule 4 at 5-C to form molecule 5. Finally, EvaE can form either epi/vancosamine...

goods. Propionyl-CoA carboxylase forms D-methylmalonyl-CoA, which is epimerized to L-methylmalonyl-CoA and converted by methylmalonyl-CoA mutase to succinyl-CoA...

A, Li JP, Oscarson S, Lindahl U (2004). "Irreversible glucuronyl C5-epimerization in the biosynthesis of heparan sulfate". J. Biol. Chem. 279 (15): 14631–8...

than does epimerization of C7, supporting the trend of decreased SAR correlation at core chiral centers on the aliphatic chain. Epimerization at C3, the...

dehydrogenase-like short-chain dehydrogenases/reductases in the oxidation and epimerization of 3alpha-hydroxysteroids in human tissues". Endocrinology. 148 (5):...

pure ketone 18c using Red-Al followed by basic work-up resulted in epimerization to give the required trans-fused diol 19 in 88% yield. As shown in Scheme...

(PCP), condensation (C), and depending on the amino acid position, an epimerization (E). The adenylation subdomain is used in activating the specific amino...

6-phosphate: anomeric form used by phosphomannose isomerase and its 1-epimerization by phosphoglucose isomerase". The Journal of Biological Chemistry. 248...

Following the IPNS pathway, further enzymes are responsible for the epimerization of isopenicillin N to penicillin N, the derivitazation to other penicillins...

nucleotides in the interconversion of sugars of higher plants. The 4-epimerization and decarboxylation of DUP-d-glucuronic acid by extracts of Phaseolus...

It is thought that under the reaction conditions, the chloro ether can epimerize and thiourea can stereoselectively bind chloride to form a closely associated...

Robinson demonstrated its conversion to dehydroepiandrosterone 6 (note the epimerized hydroxyl group) also already a known compound. Conversion of 6 to pregnenolone...

KEGG Pathway Database. Ruis H, Hoffmann-Ostenhof O (1969). "Enzymic epimerization of sequoyitol to D-pinitol in Trifolium incarnatum". Eur. J. Biochem...

(β/α)7β‑barrel (TIM‑barrel) fold which primarily catalyze metal-assisted epimerization/racemization or β-elimination of carboxylate substrates. The Haloacid...

bile acids, including deconjugation, dehydroxylation, oxidation, and epimerization. Clostridium scindens in particular employs a mechanism called 7ɑ-dehydroxylation...

cyclized, hydroxylated, Trp-Cys cross-linked to form tryptathionine, and epimerized to form a D-Thr. The order and exact biochemical mechanism for these steps...

sialic acid. to produce ManNAc and pyruvic acid. By base catalysed epimerization of N-acetyl glucosamine. By rhodium (II)-catalyzed oxidative cyclization...

Nickson, A.; Mahajan, J.; McGuire, F. (1961). "Communications- Epimerization in a Nitrite Ester Photolysis". The Journal of Organic Chemistry. 26...

KEGG Pathway Database. Ruis H, Hoffmann-Ostenhof O (1969). "Enzymic epimerization of sequoyitol to D-pinitol in Trifolium incarnatum". Eur. J. Biochem...

synthesis of cytidine diphosphate 3,6-dideoxyhexoses. II Reversible 2-epimerization of cytidine diphosphate paratose". J. Biol. Chem. 241 (18): 4275–82...

11-hydroxysulfate, and 21-N-sulfocarbamoyl substitutions as well as epimerization at the C-11 position. NSTX is quite similar to saxitoxin, like all the...

0073. PMID 1354366. Yeh WK, Ghag SK, Queener SW (1992). "Enzymes for epimerization of isopenicillin N, ring expansion of penicillin N, and 3'-hydroxylation...

Organocatalytic Asymmetric Heterodomino Reactions: The Knoevenagel/Diels−Alder/Epimerization Sequence for the Highly Diastereoselective Synthesis of Symmetrical...

D-ononitol (1-D-4-O-methyl-myo-inositol) via myo-inositol. Ononitol is epimerized to yield D-pinitol via a D-ononitol epimerase using NADPH as a cofactor...

only R-ibuprofen can be converted into ibuprofenoyl-CoA, which is then epimerized by AMACR. Conversion of S-ibuprofenoyl-CoA to S-ibuprofen is assumed to...

ββ-ester unreacted is that in addition to being hydrolyzable, it can also epimerize to the energetically more favorable trans configuration. This can happen...

(1999). "Earliest modern humans in southern Africa dated by isoleucine epimerization in ostrich eggshell". Quaternary Science Reviews. 18 (13): 1537–1548...

biocompatibility of alginate/poly-l-lysine/alginate microcapsules by the use of epimerized alginate as a coating". J Biomed Mater Res A. 64 (3): 533–9. doi:10.1002/jbm...

The product is called Lipid IECA. Step 2: WecB takes UDP-GlcNAc and epimerizes it at carbon 2. This makes UDP-N-acetylmannosamine. Step 3: WecC forms...

degree of stereoselectivity, suggesting that the reaction involves epimerization during reduction. This idea was supported by deuterium studies employing...

principle products if one follows the above steps. It is possible to epimerize the product to the desired RS/SR diastereomers, but the equilibrium is...

Ewa; Schofield, Christopher J.; Siegbahn, Per E. M. (30 April 2006). "Epimerization and desaturation by carbapenem synthase (CarC). A hybrid DFT study"...

the polypeptide. In addition, modules 2, 4, and 5 have E regions that epimerize (switch the stereochemistry) of the added amino acid to produce the correct...