34 research outputs found
Overproduction of lysine by mutant strains of Escherichia coli with defective lysine transport systems
Partial Purification and Characterization of Dihydrodipicolinic Acid Synthetase from Sporulating Bacillus megaterium
Improvement of Escherichia coli strains overproducing lysine using recombinant DNA techniques
Improved L-lysine production by the amplification of theCorynebacterium glutamicum dapA gene encoding dihydrodipicolinate synthetase inE. coli
Regulation of lysine and threonine synthesis in carrot cell suspension cultures and whole carrot roots
Meso-alpha,epsilon-diaminopimelate D-dehydrogenase: distribution and the reaction product
Increased lysine synthesis in tobacco plants that express high levels of bacterial dihydrodipicolinate synthase in their chloroplasts
Lysine and threonine metabolism are subject to complex patterns of regulation in Arabidopsis
The Chemical and Biological Degradation of Petroleum: A Foremost Challenge for the Analytical Chemist
Characterization of a novel N-acetylneuraminic acid lyase favoring industrial N-acetylneuraminic acid synthesis process
N-Acetylneuraminic acid lyase (NAL, E.C. number 4.1.3.3) is a Class I aldolase that catalyzes the reversible aldol cleavage of N-acetylneuraminic acid (Neu5Ac) from pyruvate and N-acetyl-D-mannosamine (ManNAc). Due to the equilibrium favoring Neu5Ac cleavage, the enzyme catalyzes the rate-limiting step of two biocatalytic reactions producing Neu5Ac in industry. We report the biochemical characterization of a novel NAL from a “GRAS” (General recognized as safe) strain C. glutamicum ATCC 13032 (CgNal). Compared to all previously reported NALs, CgNal exhibited the lowest kcat/Km value for Neu5Ac and highest kcat/Km values for ManNAc and pyruvate, which makes CgNal favor Neu5Ac synthesis the most. The recombinant CgNal reached the highest expression level (480 mg/L culture), and the highest reported yield of Neu5Ac was achieved (194 g/L, 0.63 M). All these unique properties make CgNal a promising biocatalyst for industrial Neu5Ac biosynthesis. Additionally, although showing the best Neu5Ac synthesis activity among the NAL family, CgNal is more related to dihydrodipicolinate synthase (DHDPS) by phylogenetic analysis. The activities of CgNal towards both NAL's and DHDPS' substrates are fairly high, which indicates CgNal a bi-functional enzyme. The sequence analysis suggests that CgNal might have adopted a unique set of residues for substrates recognition