title: Coimmobilization of l-methioninase and glutamate dehydrogenase: Novel approach for L-homoalanine synthesis.
abstract: L-Homoalanine, a nonnatural amino acid that is rarely found in human and microorganisms, is used in the synthesis of various medically pivotal antiepileptic drugs and antituberculosis compounds. l-Homoalanine can be synthesized by different enzymatic approaches. In this article, the synthesis of l-homoalanine from l-methionine was explored by coimmobilization of Aspergillus flavipes l-methioninase (AfMETase) and glutamate dehydrogenase (GDH) on polyacrylamide and chitosan. Polyacrylamide coimmobilized AfMETase and GDH displayed a maximum reactivity for the synthesis of homoalanine from l-methionine. The chitosan-coimmobilized AfMETase and GDH retain about 70% of their initial activity of l-homoalanine production by the fifth catalytic reusability cycle as compared with 50% for polyacrylamide coimmobilizate. Catalytic conditions were optimized for the maximum yield of homoalanine. Homoalanine was purified by cationic and anionic chromatographs and the proton nuclear magnetic resonance (H-NMR) analysis of the lyophilized sample displayed a unique chemical structure identical to the authentic homoalanine. Using dependable dual action of AfMETase and GDH immobilized on a solid support is a novel approach for in vitro enzymatic synthesis of l-homoalanine from l-methionine, and the immobilized enzymes can be reused many times without any significant loss of their activities.
authors.affiliation: Department of Microbiology, Faculty of Science, Zagazig University, Zagazig, 44519, Egypt.|Nano-Engineering Department, University of California, San Diego, CA, 92093, USA.
authors.forename: Ashraf S A
authors.initials: AS
authors.lastname: El-Sayed
authors.affiliation: Department of Microbiology, Faculty of Science, Zagazig University, Zagazig, 44519, Egypt.
authors.forename: Marwa A
authors.initials: MA
authors.lastname: Yassin
authors.affiliation: Proteomics and Metabolomics Facility, Department of Microbiology, Colorado State University, Fort Collins, CO, 80523-2021, USA.
authors.forename: Hend
authors.initials: H
authors.lastname: Ibrahim
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry; D000613:Aminobutyrates / Q000138:chemical synthesis*; D001230:Aspergillus / Q000201:enzymology*; D013437:Carbon-Sulfur Lyases / Q000737:chemistry*; D048271:Chitosan / Q000737:chemistry; D004800:Enzymes, Immobilized / Q000737:chemistry*; D005969:Glutamate Dehydrogenase / Q000737:chemistry*; D006801:Humans; D000099166:Polyacrylamides
chemical_list: D000180:Acrylic Resins; D000613:Aminobutyrates; D013437:Carbon-Sulfur Lyases; D048271:Chitosan; D004800:Enzymes, Immobilized; D005969:Glutamate Dehydrogenase; D000099166:Polyacrylamides; C012223:alpha-aminobutyric acid; C021558:L-methionine gamma-lyase
keywords: AfMETase; GDH; H-NMR; chitosan; coimmobilization; homoalanine; polyacrylamide