The triose phosphate
isomerase protein, identified in spot 9, relates to the metabolism of carbohydrates, acting as an important enzyme of the glycolytic pathway.
system([dagger]) Aspartate aminotransferase (AAT) 126.96.36.199 I Aconitase (ACO) 4.2..1.3 II Leucine aminopeptidase (LAP) 188.8.131.52 II Malate dehydrogenase (MDH) 1A.1.37 III Phosphogluconate dehydrogenase (PGD) 184.108.40.206 III Phosphoglucoisomerase (PGI) 220.127.116.11 I Shikimate dehydrogenase (SKI)) 18.104.22.168 III Triose phosphate
isomerase (TPI) 22.214.171.124 III ([dagger]) System I (Ashton and Braden, 1961); System II (Clayton and Tretiak, 1972); and System III (Stuber et al., 1977).
Hyperglycemia results in increased levels of triose phosphates
, dihydroxyacetone phosphate (DHAP) and glyceraldehyde-3-phosphate (GA3P) in the cells leading to high flux of these triose phosphates
to highly reactive methylglyoxal (MGO) formation.
It is suggested NAD+ to some degree regulates formation of aberrant proteins and generation of oxygen free-radicals and reactive oxygen species (ROS), because when NAD+ is limiting, glycolytic triose phosphates
spontaneously decompose into methylglyoxal (MG), a highly deleterious glycating agent and ROS inducer.
Despite deproteinization of the erythrocytes, we found large intraassay variations for the triose phosphates
and hexose phosphates, which were ascribed to enzymatic conversion.
For instance, improvements in the capacity to convert triose phosphates
to starch and sucrose might enhance productivity under conditions of low temperature and high light.
It is suggested that NAD(+) availability strongly affects cellular aging and organism lifespan: low NAD(+) availability increases intracellular levels of glycolytic triose phosphates
(glyceraldehyde-3-phosphate and dihydroxyacetone-phosphate) which, if not further metabolized, decompose spontaneously into methylglyoxal (MG), a glycating agent and source of protein and mitochondrial dysfunction and reactive oxygen species (ROS).