Maltose periodate oxidation

The rate of oxidation of ethylene glycol was found268-269 to attain a broad maximum between pH 2.5 and 6. In a very complete study of the effect of pH on the periodate oxidation of carbohydrates, Neumiiller and Vasseur260 showed that the oxidation of maltose, melibiose, methyl a-D-... 

A /3-amylase isolated from culture filtrates of Bacillus polymyxa released maltose from amylose-like substrates, but it had only limited or no action on amylopectin, periodate-oxidized amylose, and cycloamyloses. ... 

Oxidation — Apart from C02 and H20, there are three series of products that result from the oxidation of saccharide. They are 2,3-dialdehydes (5.43 and 5.49) formed on the oxidative cleavage of saccharides (5.42 and 5.48) with periodates, the sole oxidants providing such course of oxidation. Such dialdehydes are considered toxic. Further oxidation of dialdehydes leads to glyceric acid (5.45), glyoxalic acid (5.47), hydroxypyruvic acid (5.46), and erythronic acid (5.51), as shown below for the oxidative cleavage of sucrose (5.42) and maltose (5.48). 

The formaldehyde formed in a periodate reaction is determined gravimet-rically with Dimedon, or colorimetrically with chromotropic acid, after the excess oxidant is destroyed with ethylene glycol, stannous chloride, sodium arsenite, or sodium bisulfite 221), The formic acid is generally titrated directly. Titration to pH 6.0 will measure all the formic acid present. Titration to higher alkalinities will usually measure any formic acid bound as an ester 222) but also other acidic products the end-point may be indefinite. Sucrose will give 80 to 90 % of the theoretical formic acid, and maltose and lactose similarly low values. Both formaldehyde and formic acid are attacked only extremely slowly by periodate, but light apparently accelerates an oxidation to carbon dioxide and water 223),... 

Saccharose consumes 3 moles (cf. Reaction 4.113) and maltose 4 moles of periodate. The final conclusion as to sugar linkage positions and ring structure is drawn from the periodate consumption, the amount of formic acid produced (in the case of saccharose, 1 mole maltose, 2 moles) and the other carbonyl fragments which are oxidized additionally by bromine to stable carboxylic acids and then released by hydrolysis. The glycol splitting reaction should be considered an optional or complementary method to the permethylation reaction applied in structural elucidation of carbohydrates. 

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