Increased productivity of l-2-aminobutyric acid and total turnover number of NAD+/NADH in a one-pot system through enhanced thermostability of l-threonine deaminase

Enzymatic Biosynthesis of l-2-Aminobutyric Acid by Glutamate Mutase Coupled with l-Aspartate-β-decarboxylase Using l-Glutamate as the Sole Substrate

“…An important unnatural amino acid, l -2-aminobutyric acid (L-ABA), is a key chiral precursor for the production of the antiepileptic levetiracetam and brivaracetam and the antituberculosis ethambutol . Chemical synthesis of L-ABA from α-halogen acid and butanone acid reduction is environmentally unfriendly due to the toxicity of the chemicals used and the difficulty in separation and purification. , An enzymatic synthesis of L-ABA combines deamination of l -threonine by l -threonine deaminase and amination of 2-oxobutyric acid to form L-ABA using dehydrogenases or transaminases. − There are some technical problems, such as the requirement for amino donors ( l -aspartic acid or benzylamine), , uncontrollability of reaction equilibrium, formation of the byproduct l -alanine, and the need for an external cofactor (NADH) regeneration system, , which are inconvenient in industry. These involute processes of L-ABA synthesis have resulted in prohibitive prices of the drugs using L-ABA as a key chiral precursor, and a cost-effective synthesis route that avoids the above-mentioned obstacle is anticipated.…”

“…After 4 h of incubation, 90% of the l -glutamate (4.5 mM) was converted and 4.45 mM of L-ABA was detected; the percent conversion from l -glutamate to L-ABA was up to 98.9% (Figure ). This is the first time L-ABA synthesis uses l -glutamate as a sole substrate, which avoids the technical problems in current L-ABA industrial production, such as the requirement for amino donors, , control reaction equilibrium, and an external cofactor (NADH) regeneration system. , Different natural enzymes or engineered enzymes with special properties combined to develop a novel biosynthetic route for nonnatural products are emerging concepts in biocatalysis. − The novel process for L-ABA synthesis described here is a more cost-effective L-ABA production process, which will significantly reduce the prices of related drugs.…”

“…2,3 An enzymatic synthesis of L-ABA combines deamination of Lthreonine by L-threonine deaminase and amination of 2oxobutyric acid to form L-ABA using dehydrogenases or transaminases. 4−6 There are some technical problems, such as the requirement for amino donors (L-aspartic acid or benzylamine), 6,7 uncontrollability of reaction equilibrium, 6 formation of the byproduct L-alanine, 6 and the need for an external cofactor (NADH) regeneration system, 8,9 which are inconvenient in industry. These involute processes of L-ABA synthesis have resulted in prohibitive prices of the drugs using L-ABA as a key chiral precursor, and a cost-effective synthesis route that avoids the above-mentioned obstacle is anticipated.…”

A Tri‐Enzyme Cascade for Efficient Production of L‐2‐Aminobutyrate from L‐Threonine

“…Furthermore, it can inhibit the transmission of neural information and promote metabolism in brain cells. [3] The optical purity of chiral drugs is critical to their efficacy and safety. For example, levetiracetam (R) has no antiepileptic activity and ethambutol (2R, 2R') can cause blindness.…”

Active-site engineering of ω-transaminase from Ochrobactrum anthropi for preparation of L-2-aminobutyric acid

“…In the reductive amination process with dehydrogenase using L-threonine as the precursor, formate dehydrogenase (FDH) is added to regenerate NADH. However extra NAD + must be added to the mixture during the reaction in a timely fashion to guarantee the complete bioconversion of L-threonine to L-ABA [ 7 ]. Hence, the high cost of NAD + limited its application in the industry.…”