Amadori, products

The generation of artifacts has also been an intermittent concern. Hayashi et al.59 reported a heat-induced artifact for conversion of Amadori products of the Maillard reaction to V -(carboxymcthyl) lysine that had the potential to affect IHC staining. However, among thousands of articles pertaining to... 

Miki Hayashi C, Nagai R, Miyazaki K, et al. Conversion of Amadori products of the Maillard reaction to N(epsilon)-(carboxymethyl)lysine by short-term heating possible detection of artifacts by immunohistochemistry. Lab. Invest. 2002 82 795-808. 

To confirm these relationships, the ability of these intermediates to generate the free radical was also examined. As shown in Fig. 8, the Amadori product did not provide any free radical on heating alone or with added sugar or amino acid. In contrast to this, glucosyl-8-alanine alone gave the free radical to an extent similar to that in the glucose-8-alanine system. In a separate run, the Schiff base, glucosyl-n-butylamine, alone in... 

High-performance liquid chromatography has been used for the separation of Amadori products (2 ) and for the isolation of 3,8-dihydroxy-2-methylchromone from the products of xylose degradation at 100° (J3). In 1981 (4j we reported an HPLC separation scheme for the colored products of the xylose/glycine reaction. 

Data from Table I point out that other milk-based products are likely to form Amadori products, in this case lactulose-lysine and fructose-lysine, even under moderate thermal treatments. The furosine content, originating from the acid hydrolysis of Amadori products, was high in a whipping agent made from sugar and Na caseinate. It is surprising, however, that cheeses have also relatively high furosine levels. 

Our experiments on the antioxidative effect of soya-crumbs are summarized in Table III. Surprisingly milk-crumb had no effect at any pH value, although the opposite could be expected from its high level of Amadori products. 

The potential toxicity of the Amadori products (e.g. fructose-lysine) is still uncertain. The high levels of furosine in the milk-crumb add to the need to settle this question. 

Detection of Amadori Products Various methods are now available for the detection and quantification of Amadori products in body proteins (Figure 3). The furosine method, developed by Finot et al. (15), allows the quantification of glycosylated lysine residues. It has been used recently by Dolhover, et al. 

Finally, membrane proteins are also increasingly glycosylated in diabetes (65). Reid, et al. (68) recently identified an anti-M alloagglutinin in juvenile-onset diabetes that would agglutinate M-positive cells that had been pre-incubated in glucose. This suggests that Amadori products could act as haptens and elicit an immune reaction towards glycosylated tissues. 

When the structure of a compound is known, the current British-Ameri-can practice42 will be followed. No specific recommendation was made for naming Amadori rearrangement products, but, under Rule 8, the systematic name for the Amadori product of JV-i>-glucosyl-DL-leucine could be 1-(dl-l-carboxy-3-methylbutyl)amino-l-deoxy-D-fructose (I or II), and this name conflicts with the requirement that the carboxyl function takes precedence and that the name should end in acid. Consequently, this compound should be named as N- (n-ara zno-tetrahydroxy-2-oxohexyl)-DL-leucine. A shorter and equally unambiguous name would be l-(DL-leucino)-l-deoxy-D-fructose. (This is sometimes shortened to DL-leucino-deoxyfructose. Such compounds have also been called fructose-leucine, but this is not recommended since it may be confused with such expressions as the fructose-leucine system.11)... 

N-Glycosylamino acids are stronger acids than the free amino acids.61 This fact would explain an observation137 that acidic products are formed during the Maillard reaction but the enolic form of the Amadori product might also be expected to show stronger acidic properties than the simple amino acids. A-n-Glucosylglycine is rapidly hydrolyzed in dilute acetic... 

Figure 7. Molecular ion envelope of glycosylated lysozyme Amadori products (top) and cesium iodide reference mass cluster ions (bottom). The centroided masses of the tiro labeled peaks are 16,265 and 16,427 corresponding to lysozyme Amadori adducts containing 12 (G 12) and 13 (G=13) glucose residues respectively.

Although some investigators believe that dihydrofuranone is derived from ribose-5-phosphate through a dephosphorylation-dehydration mechanism, others believe it can be formed by a typical Halliard reaction betveen amines and sugars, in which the Amadori products dehydrate and eliminate to amines. Both routes are likely to occur. 

With time, the increased glucose concentration leads to glycosylation of the proteins over Amadori products to advanced glycosylation products (AGEs) and cross-linking between proteins. This degenerative process leads to the so-called late diabetic complications (LDC) after some decades. The four main complications are ... 

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