- Reactivity of Tyrosyl–Proline toward Benzoylation in Aqueous 1,4-Dioxane
-
Abstract: The kinetics of the reaction of L-tyrosyl-L-proline (Tyr–Pro) with di- andtrinitrophenyl benzoates in aqueous 1,4-dioxane (40 wt percent of water) were studiedin the temperature range 298–313 K. The reaction rate constant k298 was fou
- Khachatryan, D. S.,Kochetova, L. B.,Kustova, T. P.,Lokteva, I. I.
-
p. 1034 - 1040
(2020/07/25)
-
- Reactivity of α-Amino Acids in the Reaction with Esters in Aqueous–1,4-Dioxane Media
-
The kinetics of the reaction of a series of α-amino acids with 4-nitrophenyl acetate, 4-nitrophenyl benzoate, and 2,4,6-trinitrophenyl benzoate in aqueous 1,4-dioxane medium has been studied. Kinetics of the reactions involving 4-nitrophenyl acetate and 2,4,6-trinitrophenyl benzoate has complied with the Br?nsted dependence and revealed linear correlation between rate constant logarithm and the energy difference of the frontier orbitals of α-amino acids anions.
- Kochetova,Kustova,Kuritsyn
-
-
- A "catch-and-release" protocol for alkyne-tagged molecules based on a resin-bound cobalt complex for peptide enrichment in aqueous media
-
The development of new and mild protocols for the specific enrichment of biomolecules is of significant interest from the perspective of chemical biology. A cobalt-phosphine complex immobilised on a solid-phase resin has been found to selectively bind to a propargyl carbamate tag, that is, "catch", under dilute aqueous conditions (pH 7) at 4-°C. Upon acidic treatment of the resulting resin-bound alkyne-cobalt complex, the Nicholas reaction was induced to "release" the alkyne-tagged molecule from the resin as a free amine. Model studies revealed that selective enrichment of the alkyne-tagged molecule could be achieved with high efficiency at 4-°C. The proof-of-concept was applied to an alkyne-tagged amino acid and dipeptide. Studies using an alkyne-tagged dipeptide proved that this protocol is compatible with various amino acids bearing a range of functionalities in the side-chain. In addition, selective enrichment and detection of an amine derived from the "catch and release" of an alkyne-tagged dipeptide in the presence of various peptides has been accomplished under highly dilute conditions, as determined by mass spectrometry. Catch and release: The specific enrichment of alkyne-tagged molecules has been achieved by using cobalt beads. A cobalt complex bound to a resin was found to selectively "catch" a propargyl carbamate tag under dilute aqueous conditions (see scheme). Upon acidic treatment of the alkyne-cobalt complex, the Nicholas reaction was induced to "release" an amine. Studies using an alkyne-tagged dipeptide proved its compatibility with various amino acids and peptides under highly dilute conditions.
- Miyazaki, Ayako,Asanuma, Miwako,Dodo, Kosuke,Egami, Hiromichi,Sodeoka, Mikiko
-
supporting information
p. 8116 - 8128
(2014/07/07)
-
- Chemo-enzymatic preparation of chiral 3-aminopyrrolidine derivatives
-
A new simple method for the enantioselective enzymatic hydrolysis of N-protected D-asparagine esters suitable for the use on the preparative scale is presented. Due to major obstacles observed under conventional reaction conditions - racemization of the retained ester and a strong enzyme inactivation - a comparatively low pH together with an organic co-solvent had to be employed. Under these conditions, nearly all tested proteases demonstrated good activity and excellent enantioselectivity giving access to the corresponding D-esters and L-asparagines in high optical purities (>95% ee) and good chemical yields (>40%). From the unnatural D-asparagine derivative, sequential cyclization, selective deprotection and reduction yielded efficiently benzyl protected (R)-3-aminopyrrolidine, a homo-chiral building block utilized in numerous drug candidates.
- Iding, Hans,Wirz, Beat,Rogers-Evans, Mark
-
p. 647 - 653
(2007/10/03)
-
- HIV protease inhibitors based on amino acid derivatives
-
A compound selected from the group consisting of a compound of formula I 1a compound of formula II 2and when the compound of formula I and II comprises an amino group pharmaceutically acceptable ammonium salts thereof, wherein R1, R2, Cx, n, R3, R4, R5, Y are as defined in the specification.
- -
-
-
- Beauveria bassiana ATCC 7159 contains an L-specific α-amino acid benzamidase
-
Biotransformation of a series of racemic N-benzoyl α-amino acids by the fungus Beauveria bassiana ATCC 7159 results in isolation of the corresponding D-amino acid benzamides in high enantiomeric purity and yield.
- Holland, Herbert L.,Andreana, Peter R.,Salehzadeh-Asl, Reza,Van Vliet, Aaron,Ihasz, Nancy J.,Brown, Frances M.
-
p. 667 - 672
(2007/10/03)
-
- The utilization of alanine, glutamic acid, and serine as amino acid substrates for glycine N-acyltransferase.
-
The conjugation of benzoyl-CoA with the aliphatic and acidic amino acids by glycine N-acyltransferase, as well as the amides of the latter group, was investigated. Bovine and human liver benzoyl-amino acid conjugation were investigated using electrospray ionization tandem mass spectrometry (ESI-MS-MS). Bovine glycine N-acyltransferase catalyzed conjugation of benzoyl-CoA with Gly (Km(Gly) = 6.2 mM), Asn (Km(Asn) = 129 mM), Gln (Km(Gln) = 353 mM), Ala (Km(Ala) = 1573 mM), Glu (Km(Glu) = 1148 mM) as well as Ser in a sequential mechanism. In the case of the human form, conjugation with Gly (Km(Gly) = 6.4 mM), Ala (Km(Ala) = 997 mM), and Glu was detected. The presence of these alternative conjugates did not inhibit bovine glycine N-acyltransferase activity significantly. Considering the relatively low levels at which these conjugates are formed, it is unlikely that they will have a significant contribution to acyl-amino acid conjugation under normal conditions in vivo. However, their cumulative contribution to acyl-amino acid conjugation under metabolic disease states may prove to have a useful contribution to detoxification of elevated acyl-CoAs.
- van der Westhuizen,Pretorius,Erasmus
-
p. 102 - 109
(2007/10/03)
-