ChemInform Abstract: Biocatalytic Asymmetric Synthesis of Unnatural Amino Acids Through the Cascade Transfer of Amino Groups from Primary Amines onto Keto Acids.

ChemInform ◽  
2014 ◽  
Vol 45 (16) ◽  
pp. no-no
Author(s):  
Eul-Soo Park ◽  
Joo-Young Dong ◽  
Jong-Shik Shin
Keyword(s):  
Amino Acids ◽  
Asymmetric Synthesis ◽  
Unnatural Amino Acids ◽  
Primary Amines ◽  
Amino Groups ◽  
Keto Acids

Asymmetric Synthesis of Unnatural Amino Acids and Tamsulosin Chiral Intermediate

2013 ◽  
Vol 43 (21) ◽  
pp. 2892-2897 ◽  
Author(s):  
Veera Reddy Arava ◽  
Srinivasulu Reddy Amasa ◽  
Bharat Kumar Goud Bhatthula ◽  
Laxmi Srinivas Kompella ◽  
Venkata Prasad Matta ◽  
...  
Keyword(s):  
Amino Acids ◽  
Asymmetric Synthesis ◽  
Unnatural Amino Acids

Asymmetric synthesis of aromatic β-amino acids using ω-transaminase: Optimizing the lipase concentration to obtain thermodynamically unstable β-keto acids

2015 ◽  
Vol 11 (1) ◽  
pp. 185-190 ◽  
Author(s):  
Sam Mathew ◽  
Seong-Su Jeong ◽  
Taeowan Chung ◽  
Sang-Hyeup Lee ◽  
Hyungdon Yun
Keyword(s):  
Amino Acids ◽  
Asymmetric Synthesis ◽  
Keto Acids

scholarly journals Well-Defined Construction of Functional Macromolecular Architectures Based on Polymerization of Amino Acid Urethanes

Biomedicines ◽  
2020 ◽  
Vol 8 (9) ◽  
pp. 317
Author(s):  
Takeshi Endo ◽  
Atsushi Sudo
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Primary Amines ◽  
Amino Groups ◽  
Molecular Weights ◽  
Antifouling Coatings ◽  
Onium Salts ◽  
Polypeptide Synthesis ◽  
Produce Amino Acid ◽  
Derivatives Of

Polypeptide synthesis was accomplished using the urethane derivatives of amino acids as monomers, which can be easily prepared, purified, and stored at ambient temperature without the requirement for special precautions. The urethanes of amino acids are readily synthesized by the N-carbamoylation of onium salts of amino acids using diphenyl carbonate (DPC). The prepared urethanes are then efficiently cyclized to produce amino acid N-carboxyanhydrides (NCAs). Thereafter, in the presence of primary amines, the ring-opening polymerization (ROP) of NCAs is initiated using the amines, to yield polypeptides with controlled molecular weights. The polypeptides have propagating chains bearing reactive amino groups and initiating chain ends endowed with functional moieties that originate from the amines. Aiming to benefit from these interesting characteristics of the polypeptide synthesis using the urethanes of amino acids, various macromolecular architectures containing polypeptide components have been constructed and applied as biofunctional materials in highly efficient antifouling coatings against proteins and cells, as biosensors for specific molecules, and in targeted drug delivery.

ChemInform Abstract: Asymmetric Synthesis of Unnatural Amino Acids and Tamsulosin Chiral Intermediate.

ChemInform ◽  
2013 ◽  
Vol 45 (1) ◽  
pp. no-no
Author(s):  
Veera Reddy Arava ◽  
Srinivasulu Reddy Amasa ◽  
Bharat Kumar Goud Bhatthula ◽  
Laxmi Srinivas Kompella ◽  
Venkata Prasad Matta ◽  
...  
Keyword(s):  
Amino Acids ◽  
Asymmetric Synthesis ◽  
Unnatural Amino Acids

scholarly journals Active-Site Engineering of ω-Transaminase for Production of Unnatural Amino Acids Carrying a Side Chain Bulkier than an Ethyl Substituent

2015 ◽  
Vol 81 (20) ◽  
pp. 6994-7002 ◽  
Author(s):  
Sang-Woo Han ◽  
Eul-Soo Park ◽  
Joo-Young Dong ◽  
Jong-Shik Shin
Keyword(s):  
Amino Acids ◽  
Active Site ◽  
Unnatural Amino Acids ◽  
Kinetic Resolution ◽  
Enantiomeric Excess ◽  
Active Site Residues ◽  
Alanine Scanning Mutagenesis ◽  
Content Type ◽  
Keto Acids ◽  
Steric Constraint

ABSTRACTω-Transaminase (ω-TA) is a promising enzyme for use in the production of unnatural amino acids from keto acids using cheap amino donors such as isopropylamine. The small substrate-binding pocket of most ω-TAs permits entry of substituents no larger than an ethyl group, which presents a significant challenge to the preparation of structurally diverse unnatural amino acids. Here we report on the engineering of an (S)-selective ω-TA fromOchrobactrum anthropi(OATA) to reduce the steric constraint and thereby allow the small pocket to readily accept bulky substituents. On the basis of a docking model in whichl-alanine was used as a ligand, nine active-site residues were selected for alanine scanning mutagenesis. Among the resulting variants, an L57A variant showed dramatic activity improvements in activity for α-keto acids and α-amino acids carrying substituents whose bulk is up to that of ann-butyl substituent (e.g., 48- and 56-fold increases in activity for 2-oxopentanoic acid andl-norvaline, respectively). An L57G mutation also relieved the steric constraint but did so much less than the L57A mutation did. In contrast, an L57V substitution failed to induce the improvements in activity for bulky substrates. Molecular modeling suggested that the alanine substitution of L57, located in a large pocket, induces an altered binding orientation of an α-carboxyl group and thereby provides more room to the small pocket. The synthetic utility of the L57A variant was demonstrated by carrying out the production of optically purel- andd-norvaline (i.e., enantiomeric excess [ee] > 99%) by asymmetric amination of 2-oxopantanoic acid and kinetic resolution of racemic norvaline, respectively.

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