Periodate-thiobarbituric acid

The periodate-thiobarbituric acid test developed by Waravdekar and Saslaw269 is used in the modification of Weissbach and Hur-witz229 for identification of the products of /3-eliminative cleavage. 

Most of the structural and biochemical work related to KDO is based on the estimation of the compound or its derivatives by the periodate-thiobarbituric acid (TBA) assay in its various modifications. Indeed, KDO (see Fig. 3) was discovered9 through the formation of a characteristic, purple, TBA chromophore (Xmax 549 nm) from its 8-phosphate (2), which is the product of the condensation of D-arabinose 5-phosphate with enolpyruvate phosphate, catalyzed by 3-deoxy-8-0-phosphonooctulosonate synthetase (EC 4.1.2.16) (see Scheme 1 and Section V,2). 

Deoxy-a-L-tAi o-hex-4-enopyranosyluronic acid-containing disaccharides, formed by the action of chondroitin ABC lyase and chondroitin AC lyase have been determined by a periodate-thiobarbituric acid method. ... 

Chondroitin ABC and Chondroitin AC Lyases An improved method described for the micro determination of glycosamino-glycans is based on digestion with chondroitin ABC and AC lyases. The method has, however, been published previously. The determination is based on the colour production of 4-deoxy-a-L-t/fr 4-enepyranosyluronic acid-containing disaccharides produced by the action of chondroitin ABC and AC lyases when the periodate-thiobarbituric acid method is applied to the a,j8-unsaturated disaccharides. Suitable conditions for the quantitative assay were described. 

The periodate oxidation of 9-O-acetyl and 4,9-di-O-acetyI derivatives of the methyl ester of 7V-acetyl-)8-D-neuraminic acid methyl glycoside has been studied the 9-O-acetyl group was found to hinder the oxidation, thus accounting for the low molar absorbancy coefficient of such derivatives in the periodate-thiobarbituric acid assay. The reactivity of a seven-carbon analogue of AT-acetylneuraminic acid, namely 5-acetamido-3,5-dideoxy-L-ara //io-heptulosonic acid, in the thiobarbituric acid and resorcinol assays has also been evaluated and the formation of the various chromophores discussed. ... 

A scaled-down version of the Warren method was developed that can be used to assay as little as 25 ng of NANA (Hahn et aL, 1974). A number of automated procedures based on periodate-thiobarbituric acid have been described (Kendal, 1968 Delmotte, 1968 Fidgen, 1973 Gerbant et aL, 1973). Additional spectrophotometric techniques have employed the sulfo-phospho-vanillin reaction (Saifer and Feldman, 1971) and 1,10-phenanthroline (Dimitrov, 1973). The direct Ehrlich reaction, utilizing dimethylaminobenzaldehyde, played a key role in the early studies of sialic acid chemistry and analysis (Gottschalk, 1960) and still finds occasional use although its sensitivity is considerably below that of resorcinol and thiobarbituric acid (Werner and Odin, 1952 Onodera et aL, 1965). In comparing this method with others, Onodera et al. (1965) concluded that the possibility of false chromophores requires at least two colorimetric methods for reliable estimate of sialic acid in biological materials. 

Paerels, G. B., and Schut, J., 1%5, The mechanism of the periodate-thiobarbituric acid reaction of sialic acids, Biochem. J. 96 787. 

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