Abstract
A novel substrate, 6-(4-nitrophenyl)dihydropyrimidine-2,4(1H,3H)-dione (pNO2PheDU), was chemically synthesized and analytically verified for the potential biocatalytic synthesis of enantiopure β-amino acids. The hydantoinase (EC 3.5.2.2) from Arthrobacter crystallopoietes DSM20117 was chosen to prove the enzymatic hydrolysis of this substrate, since previous investigations showed activities of this enzyme toward 6-monosubstituted dihydrouracils. Whole cell biotransformations with recombinant Escherichia coli expressing the hydantoinase showed degradation of pNO2PheDU. Additionally, the corresponding N-carbamoyl-β-amino acid (NCarbpNO2βPhe) was chemically synthesized, an HPLC-method with chiral stationary phases for detection of this product was established and thus (S)-enantioselectivity toward pNO2PheDU has been shown. Consequently this novel substrate is a potential precursor for the enantiopure β-amino acid para-nitro-β-phenylalanine (pNO2βPhe).Electronic supplementary materialThe online version of this article (doi:10.1186/s13568-015-0174-8) contains supplementary material, which is available to authorized users.
Highlights
The use of enantiopure β-amino acids is of increasing importance, since they are constituents of several biologically active secondary metabolites such as taxol, jaspamide, theopalauamide and dolastatins (Weiner et al 2010)
Since the use of enantiopure β-amino acids is of increasing interest for applications in pharmaceutical industries, we focused on a modified hydantoinase process, which is based on the well established classical hydantoinase process for the production of enantiopure α-amino acids
The viability of the first step in this proposed modified hydantoinase process, the hydrolysis of dihydrouracil as well as the hydrolysis of differently substituted dihydrouracils was shown in previous works (May et al 1998; Servi et al 2005; O’Neill et al 2011)
Summary
The use of enantiopure β-amino acids is of increasing importance, since they are constituents of several biologically active secondary metabolites such as taxol, jaspamide, theopalauamide and dolastatins (Weiner et al 2010). Since kinetic resolutions merely enable a maximum yield of 50 %, lately the application of a modified hydantoinase process was proposed (Fig. 1b) (Engel et al 2014) The latter is based on the classical hydantoinase process (Fig. 1a), which is well established in industry for the production of enantiopure α-amino acids 3 as α-(R)phenylglycine and α-(R)-p-hydroxyphenylglycine as side chains of the semisynthetic antibiotics ampicillin and amoxicillin (May et al 2000; Bommarius et al 2001). Together with the application of hydantoin racemases or spontaneous racemization of unreacted substrates (hydantoins, 1) under slightly alkaline conditions (Ware 1950; Kato et al 1987; Las HerasVazquez et al 2009), the enantioselectivity of the involved hydantoinase as well as carbamoylase cleaving the N-carbamoyl-α-amino acid 2 leads to a dynamic kinetic resolution and a maximum yield of 100 %. The enzyme was found to be enantioselective for this reaction, making pNO2PheDU (R/S)-4a) a promising precursor, since the resulting β-amino acid may offer specific properties itself as for example known for the β-amino α-hydroxy acid which is part of the antitumor agent paclitaxel (TaxolTM) or regarding downstream chemistry (Fleming et al 1993)
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
