Indium-Mediated Coupling of .alpha.-(Bromomethyl)acrylic Acid with Carbonyl Compounds in Aqueous Media. Concise Syntheses of (+)-3-Deoxy-D-glycero-D-galacto-nonulosonic Acid and N-Acetylneuraminic Acid

1995 ◽  
Vol 60 (13) ◽  
pp. 4228-4232 ◽  
Author(s):  
Tak-Hang Chan ◽  
Ming-Chao Lee
Keyword(s):  
Acrylic Acid ◽  
Carbonyl Compounds ◽  
Aqueous Media ◽  
Acetylneuraminic Acid ◽  
Nonulosonic Acid

1993 R.U. Lemieux Award Lecture Organometallic-type reactions in aqueous media—a new challenge in organic synthesis

1994 ◽  
Vol 72 (5) ◽  
pp. 1181-1192 ◽  
Author(s):  
T.H. Chan ◽  
C.J. Li ◽  
M.C. Lee ◽  
Z.Y. Wei
Keyword(s):  
Functional Groups ◽  
Organic Synthesis ◽  
Organic Solvents ◽  
Carbonyl Compounds ◽  
Aqueous Media ◽  
Coupling Reactions ◽  
Homoallylic Alcohols ◽  
Allyl Halides ◽  
Nonulosonic Acid

The development of organometallic-type reactions in aqueous media is reviewed. Coupling reactions of allyl halides with carbonyl compounds mediated by zinc, or tin, or indium in aqueous media to give homoallylic alcohols are discussed. The stereochemical outcome is compared with similar reactions in organic solvents. A concise synthesis of (+)-muscarine is used to illustrate the usefulness of aqueous organometallic-type reactions in organic synthesis. The procedure to protect–deprotect hydroxy functional groups may not be necessary in these reactions. An application in the carbohydrate area is demonstrated with the synthesis of (+)-3-deoxy-D-glycero-D-galacto-nonulosonic acid (KDN). The mechanistic possibilities of organometallic-type reactions in aqueous media are outlined.

Oxidation of α-Substituted Carbonyl Compounds to Carboxylic Acids in Aqueous Media Using Ultrasound

1997 ◽  
Vol 27 (9) ◽  
pp. 1601-1605 ◽  
Author(s):  
D. T. C. Yang ◽  
C. J. Zhang ◽  
P. P. Fu ◽  
G. W. Kabalka
Keyword(s):  
Carboxylic Acids ◽  
Carbonyl Compounds ◽  
Aqueous Media

scholarly journals Elimination of 2-keto-3-deoxy-D-glycero-D-galacto-nonulosonic acid 9-phosphate synthase activity from human N-acetylneuraminic acid 9-phosphate synthase by a single mutation

2006 ◽  
Vol 397 (1) ◽  
pp. 195-201 ◽  
Author(s):  
Jijun Hao ◽  
Willie F. Vann ◽  
Stephan Hinderlich ◽  
Munirathinam Sundaramoorthy
Keyword(s):  
Aldol Condensation ◽  
Saturation Mutagenesis ◽  
Single Mutation ◽  
Wild Type ◽  
Wild Type Enzyme ◽  
High Sequence Identity ◽  
Acetylneuraminic Acid ◽  
Nonulosonic Acid ◽  
The Impact ◽  
Phosphate Synthase

The most commonly occurring sialic acid Neu5Ac (N-acetylneuraminic acid) and its deaminated form, KDN (2-keto-3-deoxy-D-glycero-D-galacto-nonulosonic acid), participate in many biological functions. The human Neu5Ac-9-P (Neu5Ac 9-phosphate) synthase has the unique ability to catalyse the synthesis of not only Neu5Ac-9-P but also KDN-9-P (KDN 9-phosphate). Both reactions are catalysed by the mechanism of aldol condensation of PEP (phosphoenolpyruvate) with sugar substrates, ManNAc-6-P (N-acetylmannosamine 6-phosphate) or Man-6-P (mannose 6-phosphate). Mouse and putative rat Neu5Ac-9-P synthases, however, do not show KDN-9-P synthase activity, despite sharing high sequence identity (>95%) with the human enzyme. Here, we demonstrate that a single mutation, M42T, in human Neu5Ac-9-P synthase can abolish the KDN-9-P synthase activity completely without compromising the Neu5Ac-9-P synthase activity. Saturation mutagenesis of Met42 of the human Neu5Ac-9-P synthase showed that the substitution with all amino acids except leucine retains only the Neu5Ac-9-P synthase activity at levels comparable with the wild-type enzyme. The M42L mutant, like the wild-type enzyme, showed the additional KDN-9-P synthase activity. In the homology model of human Neu5Ac-9-P synthase, Met42 is located 22 Å (1 Å=0.1 nm) away from the substrate-binding site and the impact of this distant residue on the enzyme functions is discussed.

Determination of total carbonyl compounds in aqueous media

1993 ◽  
Vol 70 (9) ◽  
pp. 881-884 ◽  
Author(s):  
Natsuko Yukawa ◽  
Hitoshi Takamura ◽  
Teruyoshi Matoba
Keyword(s):  
Carbonyl Compounds ◽  
Aqueous Media ◽  
Total Carbonyl

scholarly journals Novel serine/threonine-O-glycosylation with N-acetylneuraminic acid and 3-deoxy-D-manno-octulosonic acid by bacterial flagellin glycosyltransferases

Glycobiology ◽  
2020 ◽  
Author(s):  
Aasawari Khairnar ◽  
Sonali Sunsunwal ◽  
Ponnusamy Babu ◽  
T N C Ramya
Keyword(s):  
Escherichia Coli ◽  
Clostridium Botulinum ◽  
Associated Factors ◽  
Nucleotide Sugar ◽  
Acetylneuraminic Acid ◽  
Geobacillus Kaustophilus ◽  
Nonulosonic Acid ◽  
Glycosyl Donor ◽  
Pseudaminic Acid ◽  
Substrate Promiscuity

Abstract Some bacterial flagellins are O-glycosylated on surface-exposed serine/threonine residues with nonulosonic acids such as pseudaminic acid, legionaminic acid and their derivatives by flagellin nonulosonic acid glycosyltransferases, also called motility-associated factors (Maf). We report here two new glycosidic linkages previously unknown in any organism, serine/threonine-O-linked N-acetylneuraminic acid (Ser/Thr-O-Neu5Ac) and serine/threonine-O-linked 3-deoxy-D-manno-octulosonic acid or keto-deoxyoctulosonate (Ser/Thr-O-KDO), both catalyzed by Geobacillus kaustophilus Maf and Clostridium botulinum Maf. We identified these novel glycosidic linkages in recombinant G. kaustophilus and C. botulinum flagellins that were coexpressed with their cognate recombinant Maf protein in Escherichia coli strains producing the appropriate nucleotide sugar glycosyl donor. Our finding that both G. kaustophilus Maf (putative flagellin sialyltransferase) and C. botulinum Maf (putative flagellin legionaminic acid transferase) catalyzed Neu5Ac and KDO transfer on to flagellin indicates that Maf glycosyltransferases display donor substrate promiscuity. Maf glycosyltransferases have the potential to radically expand the scope of neoglycopeptide synthesis and posttranslational protein engineering.

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