scholarly journals Erratum: Corrigendum: Characterization of a novel N-acetylneuraminic acid lyase favoring industrial N-acetylneuraminic acid synthesis process

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Wenyan Ji ◽  
Wujin Sun ◽  
Jinmei Feng ◽  
Tianshun Song ◽  
Dalu Zhang ◽  
...  
Keyword(s):  
Acid Synthesis ◽  
Synthesis Process ◽  
Acetylneuraminic Acid

scholarly journals Characterization of a novel N-acetylneuraminic acid lyase favoring industrial N-acetylneuraminic acid synthesis process

2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Wenyan Ji ◽  
Wujin Sun ◽  
Jinmei Feng ◽  
Tianshun Song ◽  
Dalu Zhang ◽  
...  
Keyword(s):  
Biochemical Characterization ◽  
Acid Synthesis ◽  
Synthesis Process ◽  
Acetylneuraminic Acid ◽  
Cleavage Activity ◽  
Rate Limiting Step ◽  
Synthesis Activity ◽  
Rate Limiting ◽  
Class I Aldolase

Abstract 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 high Neu5Ac cleavage activity in most isozyme forms, 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 apparent k cat/Km value for Neu5Ac and highest apparent k cat/Km values for ManNAc and pyruvate, which makes CgNal favor industrial Neu5Ac synthesis process in a non-equilibrium condition. 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.

Characterization of a monolayer graphitic structure

1994 ◽  
Vol 52 ◽  
pp. 760-761
Author(s):  
X. Lin ◽  
X. K. Wang ◽  
V. P. Dravid ◽  
J. B. Ketterson ◽  
R. P. H. Chang
Keyword(s):  
Three Dimensional ◽  
Single Layer ◽  
Synthesis Process ◽  
Graphitic Structure ◽  
Positive Gaussian Curvature ◽  
Graphitic Sheet ◽  
Structural And Electronic Properties ◽  
New Material ◽  
Hexagonal Network

For small curvatures of a graphitic sheet, carbon atoms can maintain their preferred sp2 bonding while allowing the sheet to have various three-dimensional geometries, which may have exotic structural and electronic properties. In addition the fivefold rings will lead to a positive Gaussian curvature in the hexagonal network, and the sevenfold rings cause a negative one. By combining these sevenfold and fivefold rings with sixfold rings, it is possible to construct complicated carbon sp2 networks. Because it is much easier to introduce pentagons and heptagons into the single-layer hexagonal network than into the multilayer network, the complicated morphologies would be more common in the single-layer graphite structures. In this contribution, we report the observation and characterization of a new material of monolayer graphitic structure by electron diffraction, HREM, EELS.The synthesis process used in this study is reported early. We utilized a composite anode of graphite and copper for arc evaporation in helium.

scholarly journals Variable Temperature Synthesis of Tunable Flame-Generated Carbon Nanoparticles

2021 ◽  
Vol 7 (2) ◽  
pp. 44
Author(s):  
Francesca Picca ◽  
Angela Di Pietro ◽  
Mario Commodo ◽  
Patrizia Minutolo ◽  
Andrea D’Anna
Keyword(s):  
Carbon Nanoparticles ◽  
Variable Temperature ◽  
Flame Temperature ◽  
Cost Effective ◽  
Synthesis Process ◽  
Electrical Mobility ◽  
Material Synthesis ◽  
Online Measurements ◽  
Degree Of Graphitization

In this study, flame-formed carbon nanoparticles of different nanostructures have been produced by changing the flame temperature. Raman spectroscopy has been used for the characterization of the carbon nanoparticles, while the particle size has been obtained by online measurements made by electrical mobility analysis. The results show that, in agreement with recent literature data, a large variety of carbon nanoparticles, with a different degree of graphitization, can be produced by changing the flame temperature. This methodology allows for the synthesis of very small carbon nanoparticles with a size of about 3-4 nm and with different graphitic orders. Under the perspective of the material synthesis process, the variable-temperature flame-synthesis of carbon nanoparticles appears as an attractive procedure for a cost-effective and easily scalable production of highly tunable carbon nanoparticles.

Characterization of glycopeptides derived from the low-density lipoprotein of hen's egg yolk

1968 ◽  
Vol 46 (8) ◽  
pp. 983-988 ◽  
Author(s):  
J. Z. Augustyniak ◽  
W. G. Martin
Keyword(s):  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Egg Yolk ◽  
Low Density ◽  
Amide Nitrogen ◽  
Acetylneuraminic Acid ◽  
Hen’S Egg ◽  
Terminal Amino ◽  
Protein Moiety

Two glycopeptides (A and B) were isolated from pronase-digested vitellenin, the protein moiety of the low-density lipoprotein of hen's egg yolk. Aspartic acid was the only N-terminal amino acid of both glycopeptides but only A contained N-acetylneuraminic acid. A contained 55% hexose (mannose), 14% hexosamine, 12% N-acetylneuraminic acid, 0.71% amide nitrogen, and its molecular weight was 2.3 × 103. The corresponding values for B were 64, 17, 0.0, 0.75, and 2.0 × 103. Chemical analyses showed that B (and probably A) occurs in vitellenin with the heteropolysaccharide group bound N-glycosidically via the β-amide group of an asparaginyl residue. The indicated structure is R∙(NH)Asp∙Thr∙Ser∙(Ala, Gly, Val)∙Ile, where R, the heteropolysaccharide group, contains 2 hexosamine and 8 hexose residues.

Characterization of cpsF and its product CMP‐ N ‐acetylneuraminic acid synthetase, a group B streptococcal enzyme that can function in K1 capsular polysaccharide biosynthesis in Escherichia coli

1996 ◽  
Vol 19 (3) ◽  
pp. 555-563 ◽  
Author(s):  
Rachel F. Haft ◽  
Michael R. Wessels ◽  
Mary Fisk Mebane ◽  
Neil Conaty ◽  
Craig E. Rubens
Keyword(s):  
Escherichia Coli ◽  
Capsular Polysaccharide ◽  
Polysaccharide Biosynthesis ◽  
Acetylneuraminic Acid ◽  
Group B

Pharmaceutical Co-Crystal of Flufenamic Acid: Synthesis and Characterization of Two Novel Drug-Drug Co-Crystal

2017 ◽  
Vol 106 (5) ◽  
pp. 1384-1390 ◽  
Author(s):  
Sunil Kumar Nechipadappu ◽  
Venkatadri Tekuri ◽  
Darshak R. Trivedi
Keyword(s):  
Acid Synthesis ◽  
Flufenamic Acid ◽  
Synthesis And Characterization ◽  
Novel Drug

Morphology and Crystallographic Characterization of Nickel Nanowires—Influence of Magnetic Field and Current Density During Synthesis

2014 ◽  
Vol 5 (2) ◽  
Author(s):  
Mahendran Samykano ◽  
Ram Mohan ◽  
Shyam Aravamudhan
Keyword(s):  
Magnetic Field ◽  
Current Density ◽  
Quality Data ◽  
Synthesis Process ◽  
X Ray Diffraction ◽  
X Ray ◽  
Nickel Nanowires ◽  
Helium Ion ◽  
Sem Imaging

This paper presents results and discussion from a comprehensive morphological and crystallographic characterization of nickel nanowires synthesized by template-based electrodeposition method. In particular, the influence of magnetic and electric field (current density) conditions during the synthesis of nickel nanowires was studied. The structure and morphology of the synthesized nanowires were studied using Helium ion microscopy (HIM) and scanning electron microscopy (SEM) methods. The HIM provided higher quality data and resolution compared to conventional SEM imaging. The crystallographic properties of the grown nanowires were also studied using X-ray diffraction (XRD). The results clearly indicated that the morphological and crystallographic properties of synthesized nickel nanowires were strongly influenced by the applied magnetic field and current density intensity during the synthesis process.

scholarly journals Enzymological characterization of a novel d-lactate dehydrogenase from Lactobacillus rossiae and its application in d-phenyllactic acid synthesis

3 Biotech ◽  
2020 ◽  
Vol 10 (3) ◽  
Author(s):  
Xi Luo ◽  
Yingying Zhang ◽  
Fengwei Yin ◽  
Gaowei Hu ◽  
Qiang Jia ◽  
...  
Keyword(s):  
Lactate Dehydrogenase ◽  
Acid Synthesis ◽  
Phenyllactic Acid
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