Amylase-iodine complex

The amylose-iodine complex is shown here. Amylase, an enzyme in your saliva, broke down the amylose in the solution you spit into, meaning there is less starch present to react with the iodine and consequently a lighter blue solution. 

Several assays (Fig. 1) are available to measure branching enzyme activity. The iodine assay is based on the decrease in absorbance of the glucan-iodine complex (Krisman, 1962) resulting from the branching of amylose or amylopectin by the enzyme, provided that a-amylases are absent from the enzyme preparation or their activity is greatly reduced by adjusting the assay conditions. 

A kinetic, two-point method for the assay of a-amylase in serum, involving spectrophotometric measurement of a starch-iodine complex, has been described. This approach avoids interferences by serum proteins and other substances that react with iodine. The method requires less than 4 min per assay, only lOjul of sample is used, and precision and accuracy are comparable to those of established procedures. 

A strong stimulating effect by thiocyanate ions has been observed during the estimation of a-amylase by the amyloclastic method. Thiocyanate ions themselves were st own to catalyse the decolorization of the starch-iodine complex and therefore may lead to wrong values during determination of... 

Yuldasheva, G.A., Zhidomirov, G.M., Ilin, A.I. (2011). A quantum-chemical model of the inhibition mechanism of viral DNA HIV-1 replication by Iodine complex compounds. Natural Science, Vol. 3, No. 7, pp. 573-579, ISSN 2150-4091 Zemke, K.J., Muller-Fahrnow, A., Jany, K. (1991). The three-dimensional structure of the bifunctional proteinase K/ alpha-amylase inhibitor from wheat (PK13) at 2.5 A resolution. PEES, Vol. 397, pp.240-242, ISSN 1742-4658... 

Amylopectin Amylopectin is similar to amylose except that the glucose chain has branches. These branches involve linkages at the -CH2OH position ( 6), which makes them a 1 —> 6 linkages. Amylopectin is water-soluble it also interacts with iodine to form a reddish-purple complex. Typically, amylopectin is ten times the size of an amylose molecule. Digestion requires (3-amylase (1 4 linkages) and a second... 

Iodates, III, 138, 157, 178 Iodic acid, as oxidant, III, 178 Iodine, adsorption by starch, I, 256 colors of products formed from starch by amylases, V, 261 as oxidant, III, 151, 169 solubility of, III, 136 Iodine starch complex, dichroism of flow of, I, 266... 

Cyclomaltohexaicosaose forms a complex with iodine-iodide anion. Each of the two amylase-like short helixes includes a polymeric chain of 13 anions. The counter ion, Ba + or NH4+, is located outside the helices and hydroxyl groups, ethylene glycol, and PEG400 molecules are coordinated to the Ba ion [184]. 

The levels of amylase in normal urine and sera have been measured using Phadebas Starch as a substrate. The sera of patients undergoing haemodialysis or treatment with heparin appear to show a rise in the levels of amylase when the amylase is measured by a starch-iodine procedure. A corresponding increase was not observed in in vitro experiments, and it was concluded that interactions between lipoproteins and starch in vivo prevent the starch-iodide complexes from forming, thereby giving a false measurement. 

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