Trans-sialidases catalyzed

Lee S, Kim B. trans-Sialidase catalyzed sialylation of P-galacto- 29. syldisaccharide with an introduction of P-galactosidase. Enzyme Microb. Technol. 2001 28 161-167. 

SCHEME 12. Selective sialylation of 2,3-di-0-(/i-D-galactopyranosyl)-i)-galactose catalyzed by Trypanosoma cruzi trans-sialidase. 

S. Schenkman, M. A. J. Ferguson, N. Heise, M. L. de Almeida, R. A. Mortara, andN. Yoshida, Mucinlike glycoproteins linked to the membrane by glycosylphosphatidylinositol anchor are the major acceptors of sialic acid in a reaction catalyzed by trans-sialidase in metacyclic forms of Trypanosoma cruzi, Mol. Biochem. Parasitol., 59 (1993) 293-303. 

R. Agusti, V. M. Mendoza, C. Gallo-Rodriguez, and R. M. de Lederkremer, Selective sialylation of 2,3-di-0-( j -D-galactopyranosyl)-D-galactose catalyzed by Trypanosoma cruzi trans-sialidase, Tetrahedron Asymmetry, 16 (2005) 541-551. 

The Trypanosoma cruzi trani-sialidase catalyzes the reversible transfer of NeuAc from a NeuAc-a-2,3-Gal-)8-OR sequence to an acceptor hearing the Gal-)8-OR motif (Scheme 42) [54], The enzyme is a particularly useful sialidase because it has very little hydrolytic activity and tends to almost exclusively catalyze transsialylation to a galactose. However a major drawback to this method is that to drive the gly-cosylation to completion, there is a need for large quantities of complex a-2,3-linked sialyl donors, which are generally difficult to obtain from natural sources. Other natural donors with a-2,6- or a-2,8-linked sialic acids have been examined but were discovered to be poor sialyl donors for a-2,3-sialylations catalyzed by T. cruzi trans-sialidase [55]. Simple aryl a-sialosides, such as the 4-nitrophenyl glycoside 122 and methylumbelliferone glycoside 130 (Scheme 43), have been found to be excellent... 

Ito and Paulson designed a cofactor regeneration system that overcomes several limitations of rran -sialidase-catalyzed sialylations (Scheme 45) [58]. The trans-sialidase is used in conjimction with a-2,3-sialyltransferase to effectively broaden the... 

Todeschini AR, Mendonfa-Previato L, Previato JO, Varki A, van Halbeek H (2000) Trans-sialidase from Trypanosoma cruzi catalyzes sialoside hydrolysis with retention of configuration. Glycobiology 10 213-221... 

Another system that couples glycohydrolase activity to glycosyltransferase activity has been reported. Ito and Paulson have developed a CMP-NeuAc recycling scheme that operates in conjunction with a tran -sialidase activity from Trypanosoma cruzi (Scheme 10) [34]. This trons-siaUdase catalyzes the reversible transfer of NeuAc from NeuAc(a2,3)Gal-OR to virtually any -linked galactoside substrate. The CMP-NeuAc recycling system is employed to circumvent the expense of the sialylated pentasaccharide donor substrate. Synthetically, NeuAc is first transferred to Gal(pi,3)-GlcNAc(pi,3)Gal(pi,4)Glc under catalysis by o2,3-SiaT. This pentasaccharide product is then a substrate for the /ran -sialidase. Several novel sialylated molecules were produced by this technique. 

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