194736-67-9

Upstream product

• 1354896-35-7 PF₁₁₇₁F 
• 95713-52-3 N-(2,4-dinitro-5-fluorophenyl)-L-alaninamide 
• 2835-81-6 2-aminobutanoic acid 
• 2623-91-8 (R)-2-aminobutyric acid 
• 95713-52-3 Nα-(2,4-dinitro-5-fluorophenyl)-D-alaninamide 

Relevant academic research and scientific papers

Zelkovamycin is an OXPHOS Inhibitory Member of the Argyrin Natural Product Family

Natural products (NPs) are an important inspirational source for developing drugs and chemical probes. In 1999, the group of ōmura reported the constitutional elucidation of zelkovamycin. Although largely unrecognized so far, this NP displays structural s

Preparation of d-threonine by biocatalytic kinetic resolution

D-Threonine is one of the important unnatural amino acids used as chiral building blocks in pharmaceutical drugs. Owing to the presence of two chiral centers, a synthetic protocol, either through chemocatalysis or biocatalysis, has not yet been available for one-step preparation of stereochemically pure d-threonine in terms of enantiomeric and diastereomeric excesses (i.e., both >99%). Here we demonstrate that facile production of d-threonine can be implemented using threonine deaminase (TD) via kinetic resolution of dl-threonine that can be readily prepared by conventional organic synthesis. TD catalyzes the dehydration/deamination of l-threonine, leading to generation of 2-oxobutyrate and ammonia. In contrast to mild substrate inhibition of the TD activity by l-threonine (i.e., apparent inhibition constant (KIapp) = 950 mM), d-threonine turned out to be a strong inhibitor (i.e., KIapp = 41 mM). In addition to the enzyme inhibitions by both enantiomers of threonine, cell lysis observed during small-scale kinetic resolutions of ≥1 M dl-threonine led us to carry out a preparative-scale reaction at 500 mM racemic substrate. The preparative-scale kinetic resolution in a 50 mL reaction mixture charged with 3 g dl-threonine and 3400 U whole cells was completed at 5 h with >99% ee of d-threonine. Product isolation by a cation-exchange chromatography led to white solid of d-threonine (1.36 g, 90.7% isolation yield). To explore whether our strategy could afford coproduction of another valuable unnatural amino acid, the pass-through solution from the cation-exchange column was further processed by a ω-transaminase (ω-TA) reaction where 2-oxobutyrate was converted to enantiopure homoalanine using isopropylamine as an amino donor. Addition of S- and R-selective ω-TA to the pass-through solution led to 93.2 and 90.9% reaction yield within 12 h with both >99% ee of the produced l- and d-homoalanine, respectively.

Deracemization of amino acids by coupling transaminases of opposite stereoselectivity

Biocatalytic deracemization of amino acids without relying on oxidase-based deamination of an unwanted enantiomer was demonstrated by coupling a-and w-transaminases displaying opposite stereoselectivity. This strategy employs isopropylamine and a keto acid as cosubstrates and is free of generation of hydrogen peroxide which is troublesome in the conventional oxidase-based methods.

Novel bioactive peptides, PF1171F and PF1171G, from unidentified ascomycete OK-128

Two cyclic peptides, PF1171F (1) and PF1171G (2), were isolated from okara fermented with the unidentified ascomycete OK-128, and their structures were determined by NMR, MS, and Marfey amino acid analysis. Both peptides showed paralytic activity against