N-Acetylneuraminate lyase

Acetyl-NAD as an alternative substrate, ABSORPTION SPECTROSCOPY N-ACETYLNEURAMINATE LYASE... 

It is noteworthy that some low organisms like a few bacterial and protozoan species possess sialic acids. This may help these parasites to survive in the host. For a similar reason it may be advantageous for some microorganisms to have at their disposal catabolic enzymes of sialic acid metabolism like sialidase and N-acetylneuraminate lyase. Strikingly, many of these organisms are pathogenic for mammals. It could well be that sialidase is required for a faster spreading of... 

In connexion with these considerations, it is intriguing to ask whether the bacteria developed biochemical pathways for the synthesis of sialic acids independently, or whether they acquired the genome for the enzymes involved from host organisms. The similarity in the biosynthetic pathways leading to sialic acid in bacteria and in higher animals lends support to the latter possibility. It is tempting to presume that such a genome transfer is also responsible for the acquisition of sialidase and N-acetylneuraminate lyase by some bacteria. Comparison of the properties of these enzymes obtained from mammalian and bacterial sources does not contradict such an event. 

The doubly labelled sialic acids N-acetyl-[2-i4C,9-3H]neuraminic acid (NOhle and Schauer 1981) and N-glycolyl-[2-i4C,9-3H]neuraminic acid (NOhle et al. 1982) were prepared from sodium[2-i4C]pyruvate and either N-acetyl-[6-3H]mannosamine or N-glycolyl-[6- H]mannosamine, with the aid of the N-acetylneuraminate lyase from Clostridium perfringens. The metabolic fate of these compounds was studied after oral and intravenous application to mice and rats. 

Maru, 1., Ohnishi, J., Ohta, Y., Tsukada, Y. Simple and large-scale production of N-acetylneuraminic acid from N-acetyl-D-glucsamine and pyruvate using N-aceyl-D-glucosamine 2-epimerase and N-acetylneuraminate lyase. Carbohydr. Res., 1998, 306, 575-578. 

N-Acetylneuraminic acid aldolase (or sialic acid aldolase, NeuA EC 4.1.3.3) catalyzes the reversible addition of pyruvate (2) to N-acetyl-D-mannosamine (ManNAc (1)) in the degradation of the parent sialic acid (3) (Figure 10.4). The NeuA lyases found in both bacteria and animals are type I enzymes that form a Schiff base/enamine intermediate with pyruvate and promote a si-face attack to the aldehyde carbonyl group with formation of a (4S) configured stereocenter. The enzyme is commercially available and it has a broad pH optimum around 7.5 and useful stability in solution at ambient temperature [36]. 

Sialic acid aldolase (SA EC 4.1.3.3), also named N-acetylneuraminate pyruvate lyase, has been extensively used by our group in its immobilized form, first for the synthesis of large amounts of N-acetylneuraminic acid [20] and then for many natural and unnatural sialic acids [21]. SA catalyzes the reversible aldol reaction of N-acetylmannosaraine and pyruvate to give N-acetylneuraminic acid with an optimum pH for activity of 7.5 and an equilibrium constant of 12.7 M in the synthetic direction (Scheme 3) [10]. 

Sialic acid aldolase 4.1.3.3 NeuA N-Acetylneuraminic acid lyase... 

Full details have been reported on the use of immobilized N-acetylneuraminate pyruvate lyase for the preparation of various 2-ulosonic acids, including KDN (see Vol. 21, p.160-161 and Vol. 23, p. 162).41 The IV-nitroso derivative (32) of NeuTVAc can be used as indicated in Scheme 10 to produce the peracetyl methyl ester (33) of KDN. Thermolysis of (32) gave alkene (34) together with the 4,5-ene and a ring-contracted product. Hydrogenation of (34) led to both the saturated compound and the hydrogenolysis product. ... 

Shukla, A. K., and Schauer, R., 1986, Analysis of sialidase and N-acetylneuraminate pyruvate lyase substrate specificity by high-performance liquid chromatography. Anal. Biochem. 158 158-164. 

A-Acetyl neuraminic acid aldolase [from Clostridium perfringens, A-acetylneuraminic acid pyruvate lyase] [9027-60-5] [EC 4.1.3.3]. Purified by extraction with H20, protamine pptn, (NH4)2S04 pptn, Me2CO pptn, acid treatment at pH 5.7 and pptn at pH 4.5. The equilibrium constant for pyruvate + n-acetyl-D-mannosamine ++ /V-acetylneuraminidate at 37° is 0.64. The Km for A-acetylneuraminic acid is 3.9mM in phosphate at pH 7.2 and 37°. [Comb and Roseman Methods in Enzymology 5 391 1962). The enzyme from Hogg kidney (cortex) has been purified 1700 fold by extraction with H20, protamine sulphate pptn, (NH4)2S04 pptn, heat treatment between 60-80°, a second (NH4)2S04 pptn and starch gel electrophoresis. The Km for A-acetylneuraminic acid is 1.5mM. [Brunetti et al. JBC 237 2447 1962). 

O-Prolected sugar thioformamides have also been prepared in 44-87% yields by tri-n-butyltin hydride reduction of isothiocyanate precursors in ether.156 For the preparation of 5-A-thioacylneuraminic acids (84), a chemoenzymatic route based on the M-acetylneuraminate pyruvate lyase-mediated condensation of the corresponding A -thioacyl-n-mannosamine derivatives (83) and sodium pyruvate has been reported.189 The enzyme-catalyzed aldol reaction was performed at pH 6.8 and afforded the desired compound in 55% yields (Scheme 24). 

A-acetyl neuraminic acid lyase (NAL) catalyzes the reversible aldol addition of N-acetylmannosamine to pyruvate to produce A-acetylneuraminic acid, a sialic acid. Sialic acid is an essential component of complex carbohydrates which are of paramount importance as recognition signals in a variety of biological process, such as parasite invasion, infectivity and survival of the invading organism in the host. Hence, sialic acids mimetics, such as the commercial Oseltamavir, Relenza and... 

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