414
2
General Synthetic Methods
⊡ Scheme 64
7 The Maillard Reaction
The Maillard reaction is a complex group of degradation/rearrangement reactions initiated by
reactions of free sugars and amines [248,249,250,251]. The reaction is of major interest for
food processing [252,253,254,255,256,257] and life sciences [258,259,260,261,262,263,264,
265]. Degeneration of amine drugs in the presence of reducing sugars as excipients and deterioration of sugar artifacts are also related to the reaction [266,267].
The nonenzymatic reaction between reducing sugars and long-lived proteins in vivo results in
the formation of glycation and advanced glycation end products, which alter the properties
of proteins including charge, helicity, and their tendency to aggregate. Such protein modifications are linked with various pathologies associated with the general aging process such as
Alzheimer disease and the long-term complications of diabetes. Although it has been suggested that glycation and advanced glycation end products altered protein structure and conformation, little structural data and information currently exist on whether or not glycation
does indeed influence or change local protein secondary structure [268]. For example, in the
blood, D-glucose can react with an NH 2 group of hemoglobin to form an imine that subsequently undergoes an irreversible rearrangement to a more stable a-aminoketone known as
hemoglobin-AIc \index{hemoglobin-AIc}% [269].
Diabetes results when the body does not produce sufficient insulin or when the insulin it produces does not properly stimulate its target cells. Because insulin is the hormone that maintains the proper level of glucose in the blood, diabetics have increased blood glucose levels.
The amount of hemoglobin-AIc formed is proportional to the concentration of glucose in the
blood, so diabetics have a higher concentration of hemoglobin-AIc than nondiabetics. Thus,
measuring the hemoglobin-AIc level is a way to determine whether the blood glucose level of
a diabetic is being controlled [270,271].
2
General Synthetic Methods
⊡ Scheme 64
7 The Maillard Reaction
The Maillard reaction is a complex group of degradation/rearrangement reactions initiated by
reactions of free sugars and amines [248,249,250,251]. The reaction is of major interest for
food processing [252,253,254,255,256,257] and life sciences [258,259,260,261,262,263,264,
265]. Degeneration of amine drugs in the presence of reducing sugars as excipients and deterioration of sugar artifacts are also related to the reaction [266,267].
The nonenzymatic reaction between reducing sugars and long-lived proteins in vivo results in
the formation of glycation and advanced glycation end products, which alter the properties
of proteins including charge, helicity, and their tendency to aggregate. Such protein modifications are linked with various pathologies associated with the general aging process such as
Alzheimer disease and the long-term complications of diabetes. Although it has been suggested that glycation and advanced glycation end products altered protein structure and conformation, little structural data and information currently exist on whether or not glycation
does indeed influence or change local protein secondary structure [268]. For example, in the
blood, D-glucose can react with an NH 2 group of hemoglobin to form an imine that subsequently undergoes an irreversible rearrangement to a more stable a-aminoketone known as
hemoglobin-AIc \index{hemoglobin-AIc}% [269].
Diabetes results when the body does not produce sufficient insulin or when the insulin it produces does not properly stimulate its target cells. Because insulin is the hormone that maintains the proper level of glucose in the blood, diabetics have increased blood glucose levels.
The amount of hemoglobin-AIc formed is proportional to the concentration of glucose in the
blood, so diabetics have a higher concentration of hemoglobin-AIc than nondiabetics. Thus,
measuring the hemoglobin-AIc level is a way to determine whether the blood glucose level of
a diabetic is being controlled [270,271].