Synthesis of nucleotide-activated oligosaccharides by beta-galactosidase from Bacillus circulans.

in Biological Chemistry (2001), 382(2), 299-311

The enzymatic access to nucleotide-activated oligosaccharides by a glycosidase-catalyzed transglycosylation reaction was explored. The nucleotide sugars UDP-GlcNAc and UDP-Glc were tested as acceptor ... [more ▼]

The enzymatic access to nucleotide-activated oligosaccharides by a glycosidase-catalyzed transglycosylation reaction was explored. The nucleotide sugars UDP-GlcNAc and UDP-Glc were tested as acceptor substrates for beta-galactosidase from Bacillus circulans using lactose as donor substrate. The UDP-disaccharides Gal(beta1-4)GlcNAc(alpha1-UDP) (UDP-LacNAc) and Gal(beta1-4)Glc(alpha1-UDP) (UDP-Lac) and the UDP-trisaccharides Gal(beta1-4)Gal(beta1-4)GlcNAc(alpha1-UDP and Gal(beta1-4)Gal(beta1-4)Glc(alpha1-UDP) were formed stereo- and regioselectively. Their chemical structures were characterized by 1H and 13C NMR spectroscopy and fast atom bombardment mass spectrometry. The synthesis in frozen solution at -5 degrees C instead of 30 degrees C gave significantly higher product yields with respect to the acceptor substrates. This was due to a remarkably higher product stability in the small liquid phase of the frozen reaction mixture. Under optimized conditions, at -5 degrees C and pH 4.5 with 500 mM lactose and 100 mM UDP-GlcNAc, an overall yield of 8.2% (81.8 micromol, 62.8 mg with 100% purity) for Gal(beta1-4)GlcNAc(alpha1-UDP) and 3.6% (36.1 micromol, 35 mg with 96% purity) for Gal(beta1-4)Gal(beta1-4)GlcNAc(alpha1-UDP) was obtained. UDP-Glc as acceptor gave an overall yield of 5.0% (41.3 micromol, 32.3 mg with 93% purity) for Gal(beta1-4)Glc(alpha1-UDP) and 1.6% (13.0 micromol, 12.2 mg with 95% purity) for Gal(beta1-4)Gal(beta1-4)Glc(alpha1-UDP). The analysis of other nucleotide sugars revealed UDP-Gal, UDP-GalNAc, UDP-Xyl and dTDP-, CDP-, ADP- and GDP-Glc as further acceptor substrates for beta-galactosidase from Bacillus circulans. [less ▲]

Method for the enzymatic galactosylation of monosaccharides and oligosaccharides

Patent (1999)

UDP-N-Acetyl-alpha-D-glucosamine as acceptor substrate of beta-1,4-galactosyltransferase. Enzymatic synthesis of UDP-N-acetyllactosamine.

in Glycoconjugate Journal (1999), 16(7), 327-36

The capacity of UDP-N-acetyl-alpha-D-glucosamine (UDP-GlcNAc) as an in vitro acceptor substrate for beta-1,4-galactosyltransferase (beta4GalT1, EC 2.4.1.38) from human and bovine milk and for recombinant ... [more ▼]

The capacity of UDP-N-acetyl-alpha-D-glucosamine (UDP-GlcNAc) as an in vitro acceptor substrate for beta-1,4-galactosyltransferase (beta4GalT1, EC 2.4.1.38) from human and bovine milk and for recombinant human beta4GalT1, expressed in Saccharomyces cerevisiae, was evaluated. It turned out that each of the enzymes is capable to transfer Gal from UDP-alpha-D-galactose (UDP-Gal) to UDP-GlcNAc, affording Gal(beta1-4)GlcNAc(alpha1-UDP (UDP-LacNAc). Using beta4GalT1 from human milk, a preparative enzymatic synthesis of UDP-LacNAc was carried out, and the product was characterized by fast-atom bombardment mass spectrometry and 1H and 13C NMR spectroscopy. Studies with all three beta4GalTs in the presence of alpha-lactalbumin showed that the UDP-LacNAc synthesis is inhibited and that UDP-alpha-D-glucose is not an acceptor substrate. This is the first reported synthesis of a nucleotide-activated disaccharide, employing a Leloir glycosyltransferase with a nucleotide-activated monosaccharide as acceptor substrate. Interestingly, in these studies beta4GalT1 accepts an alpha-glycosidated GlcNAc derivative. The results imply that beta4GalT1 may be responsible for the biosynthesis of UDP-LacNAc, previously isolated from human milk. [less ▲]

Application of recombinant sucrose synthase large scale synthesis of ADP-glucose

in Journal of Molecular Catalysis B : Enzymatic (1998), 5(1-4), 25-28

Abstract The synthesis of ADP-glucose with recombinant sucrose synthase from potato was combined with the synthesis of ADP from AMP and ATP catalysed by myokinase from rabbit muscle. By using the ... [more ▼]

Abstract The synthesis of ADP-glucose with recombinant sucrose synthase from potato was combined with the synthesis of ADP from AMP and ATP catalysed by myokinase from rabbit muscle. By using the repetitive-batch-technique we were able to reach enzyme productivities (mg ADP-glucose/U enzyme) of 28 mg/U sucrose synthase and 140 mg/U myokinase yielding 2.8 g ADP-glucose (55% yield). After product isolation, 2.2 g ADP-glucose was obtained corresponding to 44% overall yield. [less ▲]

One-pot enzymatic synthesis of the Gal alpha 1-->3Gal beta 1-->4GlcNAc sequence with in situ UDP-Gal regeneration.

in Glycoconjugate Journal (1996), 13(4), 687-92

The trisaccharide Gal alpha 1-->3Gal beta 1-->4GlcNAc beta 1-->O-(CH2)8COOCH3 was enzymatically synthesized, with in situ UDP-Gal regeneration. By combination in one pot of only four enzymes, namely ... [more ▼]

The trisaccharide Gal alpha 1-->3Gal beta 1-->4GlcNAc beta 1-->O-(CH2)8COOCH3 was enzymatically synthesized, with in situ UDP-Gal regeneration. By combination in one pot of only four enzymes, namely, sucrose synthase, UDP-Glc 4'-epimerase, UDP-Gal:GlcNAc beta 4-galactosyltransferase and UDP-Gal:Gal beta 1-->4GlcNAc alpha 3-galactosyltransferase, Gal alpha 1-->3Gal beta 1-->4GlcNAc beta 1-->O-(CH2)8COOCH3 was formed in a 2.2 mumol ml-1 yield starting from the acceptor GlcNAc beta 1-->O-(CH2)8COOCH3. This is an efficient and convenient method for the synthesis of the Gal alpha 1-->3Gal beta 1-->4GlcNAc epitope which pays an important role in various biological and immunological processes. [less ▲]

A novel three-enzyme reaction cycle for the synthesis of N-acetyllactosamine with in situ regeneration of uridine 5'-diphosphate glucose and uridine 5'-diphosphate galactose

in Journal of the American Chemical Society (1996), 118(8), 1836-1840

A new three-enzyme reaction cycle consisting of sucrose synthase, UDP glucose 4‘-epimerase, and human β-1,4-galactosyltransferase was established for the synthesis of N-acetyllactosamine (LacNAc) with in ... [more ▼]

A new three-enzyme reaction cycle consisting of sucrose synthase, UDP glucose 4‘-epimerase, and human β-1,4-galactosyltransferase was established for the synthesis of N-acetyllactosamine (LacNAc) with in situ regeneration of UDP galactose. We found that UDP glucose 4‘-epimerase is reductively inactivated in the presence of UMP and acceptor substrates of β-1,4-galactosyltransferase. Reactivation of UDP glucose 4‘-epimerase by the transition state analogues dUDP or dTDP 6-deoxy-d-xylo-4-hexulose in combination with the repetitive batch technique enabled us to use the native enzymes for 11 days in this cycle. With 10 U of sucrose synthase, 5 U of UDP glucose 4‘-epimerase, and 1.25 U of β-1,4-galactosyltransferase, 594 mg of LacNAc could be synthesized. N-Acetyllactosamine was also subsequently converted to Neu5Acα2,6Galβl,4GlcNAc with α-2,6-sialyltransferase and CMP-Neu5Ac. [less ▲]

Praeparative enzymatische Synthese von Nucleotidzuckern mit Saccharose Synthase aus Reis

Poster (1995, May 30)

ISOLATION OF SUCROSE SYNTHASE FROM RICE (ORYZA-SATIVA) GRAINS IN PILOT-SCALE FOR APPLICATION IN CARBOHYDRATE SYNTHESIS

in Biotechnology & Applied Biochemistry (1995), 21(Part 1), 29-37

The application of sucrose synthase as a valuable biocatalyst for the synthesis of activated sugars and saccharides requires large amounts of enzyme. The purification of sucrose synthase starting from the ... [more ▼]

The application of sucrose synthase as a valuable biocatalyst for the synthesis of activated sugars and saccharides requires large amounts of enzyme. The purification of sucrose synthase starting from the 9 kg scale of rice (Oryza sativa) grains was achieved in five steps with 11.3% yield and 192-fold purification. The final sucrose synthase preparation was free of nucleotide di- and monophosphatases, but did contain 0.05% of both invertase and UDP-glucose-hydrolysing activity. It can be efficiently utilized for the synthesis of activated sugars. Its application for the synthesis of saccharides is possible taking into account that 15% UDP-glucose is hydrolysed within 15 h incubation time [less ▲]